why is the sky black
Answers
Answer: The sky appears black at night due to the absence of sufficient light reaching our eyes from distant stars and galaxies.
Explanation:
The sky appears black during the night when there is no significant source of illumination. This phenomenon is known as the "night sky paradox." The reason behind the blackness of the night sky is primarily attributed to the vastness of the universe and the limitations of human vision.
During the day, the sky appears blue because of a process called Rayleigh scattering. The Earth's atmosphere scatters shorter blue wavelengths of light more than longer wavelengths, creating the blue color we observe.
At night, when the sun is no longer visible, our line of sight extends deeper into space. We can observe countless stars in various directions, implying that there should be light coming from all those stars. However, the night sky still appears dark overall.
The reason for this darkness is that the universe is not infinitely old. It has a finite age. Consequently, the light from the most distant stars and galaxies has not had enough time to reach us yet. As a result, the vast majority of the universe is beyond our observational reach, and we perceive the night sky as predominantly black.
In addition, there are other factors that contribute to the blackness of the night sky, such as interstellar dust, which absorbs and scatters light, and the absorption of light by gases and particles in our atmosphere.
Therefore, the sky appears black at night because the light from distant stars and galaxies has not reached us, and the absence of significant illumination sources contributes to the overall darkness.
Related Questions
you now know that inheritance of eye color in fruit flies is sex-linked: the gene encoding eye color is located on the x chromosome, and there is no corresponding gene on the y chromosome. how would the inheritance pattern differ if the gene for eye color were instead located on an autosome (a non-sex chromosome)? recall that for autosomes, both chromosomes of a homologous pair carry the same genes in the same locations.
Answers
If eye color exhibits autosomal (non-sex chromosome) inheritance. Then, in this case we have 100% red eyes and 0% white.
Let's suppose a cross between large number of white-eyed females with red-eyed males. Then considering two separate cases:
Case 1: Eye color exhibits sex-linked inheritance Case 2: Eye color exhibits autosomal (non-sex linked) inheritance. (In this case, assume that the red-eyed males are homozygous )
For each of this case, predict that how many of the male and female offspring would have red eyes and white eyes.
In Case 1: Eye color exhibits sex-linked inheritance If there were 100 female offspring would have red eyes and zero would have white eyes. If there were 100 male offspring zero would have red eyes and 100 would have white eyes.
And in Case 2: Eye color exhibits autosomal (non-sex-linked) inheritance. If there were 100 female offspring, 100 would have red eyes and zero would have white eyes. If there were 100 male offspring 100 would have red eyes and zero would have white eyes.
So, in this case we have 100% red eyes and 0% white.
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The _______ is an important cranial landmark, as it houses the pituitary gland.
a. crista galli
b. hyoid bone
c. foramen ovale
d. sella turcica
Answers
The sella turcica is a vital cranial landmark, as it houses the pituitary gland Thus, option D: sella turcica is the correct answer.
Within the human skull, there is a tiny, bony nook at the base of the brain that holds and protects the pituitary gland which is known as sella turcica. The pitualirty gland controls how hormones work in the human body, thus their protection is necessary. So the sella turcica serves as a cephalometric landmark that houses the pituitary gland to provide it protection.
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Your colleague has collected some sediments from a mangrove swamp and then grows the bacteria from those sediments on an agar plate to determine the concentration of bacteria in those sediments.
a) Describe why the resulting bacterial concentration is an underestimate of the actual concentration of bacteria in those sediments.
b) State what method they should have used instead to more accurately determine the bacterial concentration.
Answers
From the question;
1) It may have been underestimated sue to visibility bias
2) The method of direct microscopic count or direct cell count can be employed.
What about the bacteria?On the particular agar medium employed, not all bacteria contained in the sediments may be viable or able to grow. Some bacteria might no longer be culturable or in a dormant state, which limits their capacity to grow into colonies on the agar plate. This viability bias may lead to the underestimate of the bacterial population by excluding a sizable fraction of it.
A direct microscopic count entails using a microscope to directly observe and count bacterial cells. Without the bias imposed by culture-based approaches, it provides a more thorough count of bacterial cells, including viable and non-viable cells.
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__________ acts on groups of paired muscles. When one muscle contracts, the opposite muscle cannot contract because no stimulus is sent.
Answers
Answer:
Reciprocal innervation
Some people who take beta blockers get out of breath when they exercise.
Explain why beta blockers can have this effect during exercise.
6 MARKS,easy definition to remember
Answers
Answer:
Beta blockers slow the heart rate, which can prevent the increase in heart rate that typically occurs with exercise. This means that it might not be possible for you to reach your target heart rate, the number of heartbeats per minute you typically aim for to ensure you're exercising hard enough.
in the hershey chase experiments, the isotope 35s was used to label and the isotope 32p was used to label
Answers
In the Hershey-Chase experiment, the isotope 35S was used to label protein, and the isotope 32P was used to label DNA.The Hershey-Chase experiment was a series of experiments carried out in 1952 by Alfred Hershey and Martha Chase.
These experiments were carried out to determine the nature of the genetic material. In this experiment, the researchers used bacteriophages (viruses that infect bacteria) to investigate whether DNA or protein is the genetic material.Hershey and Chase used radioactive isotopes to label either the protein coat of the virus or the DNA inside it. The bacteriophages were then allowed to infect bacteria, and the researchers observed what happened. They found that when the virus's DNA was labeled with the radioactive isotope 32P, the radioactivity entered the bacteria. On the other hand, when the protein coat was labeled with the radioactive isotope 35S, no radioactivity was detected in the bacteria. This led to the conclusion that DNA is the genetic material that controls the characteristics of an organism.
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Salinity is the most important factor in the process of photosynthesis (T or F).
Answers
The statement "Salinity is the most important factor in the process of photosynthesis" is false because the most important factors for photosynthesis include light intensity, carbon dioxide concentration, and temperature.
While salinity can impact the growth and health of aquatic plants, the most important factors in photosynthesis are light, water, carbon dioxide, and chlorophyll. Photosynthesis is the process by which plants convert light energy into chemical energy, and it requires these key factors to function efficiently.
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5. What would be the consequence of treating the vector, before ligation, with calf intestinal phosphatase?
A. It would prevent the plasmid's DNA from reversing polarity during ligation.
B. It would prevent the ends of the plasmids from being ligated.
C. It would ligate the ends of the plasmids.
D. It would reverse the polarity of plasmids' DNA
Answers
The consequence of treating the vector, before ligation, with calf intestinal phosphatase will be B. It would prevent the ends of the plasmids from being ligated.
Calf intestinal phosphatase is a phosphatase enzyme that is derived from the intestine of the calf. The function of this enzyme is to remove the phosphatases present in the 3' and the 5' of a DNA segment by cleaving them.
Vectors, such as plasmids, are treated with the calf intestinal enzyme in order to prevent the plasmid from being ligated again. In order to add our gene of interest to the vector, the calf intestinal phosphatase is added so that the vector binds to the gene of interest rather than itself.
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What implications could this have for this species of slug from an evolutionary standpoint? What potential advantages or disadvantages might this mutation have?
Answers
Positive mutations are essential for evolution to occur. They raise a living thing's chances of surviving or procreating. Deadly mutations can give rise to cancer or genetic diseases.
Are mutations typically detrimental?While most mutations are beneficial, some can also be dangerous. A dangerous mutation might cause a genetic illness or a cancerous condition. Chromosome-level mutations are still another type. Chromosomes, which are little, threadlike organelles present in the cell nucleus, carry genes.
Why do mutations cause issues?A variation can make a protein malfunction or not be created at all by altering the gene's instructions for producing it. A variation can impair normal development or result in a disease when it changes a protein that is essential to the organism.
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In a tidepool, you discover a worm with a flattened body. What one feature would suggest that it is a nemertean rather than a platyhelminth
Answers
The one feature that would suggest that the worm is a nemertean rather than a platyhelminth is the presence of a proboscis, which is a long, muscular tube-like structure used for capturing prey.
Platyhelminths lack a proboscis, while nemerteans have a well-developed one.
In a tidepool, if you discover a worm with a flattened body, one feature that would suggest it is a nemertean rather than a platyhelminth is the presence of a proboscis. Nemerteans have a specialized, retractable, and extendable feeding organ called a proscisbo, while platyhelminths lack this feature.
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What does a chronological text structure used to signal a sequence of time?
Answers
A chronological text structure uses to signal a sequence of time is words and dates.
What is a chronological text structure?In а chronologicаl sequence, the аuthor uses the order of events, or chronology, to inform reаders аbout events or content. The events mаy be orgаnised by time or dаte, by аrrаnging events аs а series of steps or by following а list-like structure. Chronologicаl sequencing is commonly used in nonfiction texts. In nonfiction, there аre usuаlly cleаr time mаrkers such аs dаtes or times of dаy to indicаte а cleаr timeline.
Your question is incomplete, but most probably your full question was
What does a chronological text structure use to signal the sequence of time?
A. causes and effects
B. reactions to events
C. words or dates
D. responses to events
Thus, the correct answer is C.
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what are the reactants of enzyme-catalyzed reactions called?
Answers
Answer:
substrates.
Explanation:
Substrates bind to a part of an enzyme called the active site and remain bound to the enzyme until the reaction is complete, when the products are released. Temperature, pH, and regulatory molecules can affect the activity of enzymes.
Which best represents the sequence of bases on mRNA?
A UTCG
B. AUCG
C. ATCG
D. ATUG
Answers
What are cell cycle regulators
Answers
Answer: A conserved set of cyclin-dependent protein kinases (Cdks) initiate or regulate events through phosphorylation of intracellular proteins, thus controlling cell cycle progression, terminal differentiation, and apoptosis.
Explanation: Your welcome! ;D
Help me plsss
This will be a reall help
Answers
Answer:
Im no expert but i think around 50%
Answer:
50% RR, 50% Rr
100% of offspring will be round because all offspring have the dominant round gene. Hope this helps!
The Punnett square would look like this:
Which of these pairs does not correctly match a carbohydrate with its function?
Answers
Of the available options, the first one states that cellulose is a structural part of the hair, this is not correct for several reasons, first cellulose is a biopolymer characteristic of cellular walls in plants, and it's not present in animal cells, secondly human hair is formed mainly of keratin a protein, therefore their basic units are amino acids, not carbohydrates. Therefore taking this into consideration, the correct answer is option 1.
Which of these statements is NOT true of the phylogenetic tree?
Answers
The statement that is not true of the phylogenetic tree is that it ranks organisms by importance in evolutionary history. option A
Features of the phylogenetic treeA phylogenetic tree is a diagram representing evolutionary relationships among organisms. It is also known as phylogenyPhylogenetic trees are hypothesesIt reflects how species or other groups evolved from a common ancestors.Hence, the statement that is not true of the phylogenetic tree is that it ranks organisms by importance in evolutionary history. option A
The complete question is:
Which of these statements is NOT true of the phylogenetic tree?
A. It ranks organisms by importance in evolutionary history.
B. It depicts an organism's lineage as it changes over time.
C. It shows successive events of speciation in which one species gives rise to two.
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which of the following metabolic pathways is common to both fermentation and cellular respiration? select one: a. glycolysis b. the citric acid cycle c. synthesis of acetyl coa from pyruvate. d. the electron transport chain
Answers
The metabolic pathway common to both fermentation and cellular respiration is glycolysis. Therefore, the answer to the question is a. Glycolysis.
Glycolysis is the first stage of both anaerobic and aerobic cellular respiration, which occurs in the cytoplasm of cells. It is a metabolic pathway that converts glucose into pyruvate or lactate, which can be used to create ATP through fermentation or cellular respiration. The process of glycolysis takes place in ten sequential steps and is an anaerobic process that does not require oxygen to produce ATP. This metabolic pathway is common to both fermentation and cellular respiration because it is an initial step in the production of ATP in cells. Glycolysis produces 2 ATP molecules, 2 NADH molecules, and 2 pyruvate molecules. Glycolysis is the only pathway common to both fermentation and cellular respiration.
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RNA is made because DNA is always in the nucleus,but ribosomes for making proteins are found in the _______
Answers
Answer:
Cytoplasm
Explanation:
In eukaryotes, there is a definite nucleus where the ribosome and mRNA production takes place. The ribosomes and mRNA come out of the nucleus into the cytoplasm where the ribosomes work upon and catalyze the formation of proteins. Meaning that in eukaryotic cell, ribosomes make proteins in the cytoplasm.
Explanation:
Ribosome existed in the rough endoplasmic reticulum and existed freely in cytoplasm
Why is geometric dilution process needed?
Answers
The geometric dilution process is needed to ensure accurate and uniform mixing of two or more substances. This is especially important when working with potent or hazardous substances, as it helps to minimize the risk of uneven distribution and potential reactions.
By following the steps of geometric dilution, such as adding small amounts of the substance to be diluted into a larger amount of diluent, stirring well after each addition, and repeating the process until the desired concentration is achieved, you can achieve a homogeneous mixture that accurately represents the desired concentration. Therefore, the geometric dilution process is necessary to maintain precision and consistency in various scientific and laboratory applications.
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Which of the following does NOT contain structures homologous to the human arm? a. turtle flipper b. dragonfly wing c. bird wing d. bat wing e. Tiktaalik fin.
Answers
The option that does NOT contain structures homologous to the human arm is b. dragonfly wing.
Homologous structures are those that share a common evolutionary origin but may have different functions in different organisms. In the case of a turtle flipper, bird wing, bat wing, and Tiktaalik fin, the underlying bone structure is similar to the human arm, indicating a shared ancestry.
On the other hand, a dragonfly wing is not homologous to the human arm because it does not share the same evolutionary origin. The dragonfly wing is composed of a thin, membranous material supported by veins, while the human arm consists of bones, muscles, and connective tissue. This difference in structure indicates that dragonfly wings and human arms evolved independently, adapting to their respective environments and functions. Therefore, Option B is correct, the dragonfly wing is not a homologous structure to the human arm.
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Nicotine replacement and self-management techniques are two approaches to smoking__________________.
What is the name of the method in which a smoker tries to avoid tempting situations and manages feelings that lead to nicotine use?
True or False Most people pick up smoking habits in adulthood.
Making sure your friends know you are tobacco-free and sticking to that decision in the face of pressures and influences requires ________________skills.
Critical Thinking Identify 5 health benefits of smoking cessation (stop smoking) that occur throughout the years after you quit, as well as those you see within a few days.
Can someone pls help me.
Answers
Answer:
It requires trolling your friends skills
(T/F) high-protein diets do not increase water loss.
Answers
The following statement “high-protein diets do not increase water loss.” is False.
High-protein diets can increase water loss in the body. When proteins are metabolized, they produce waste products, such as urea, which need to be excreted by the kidneys.
The excretion of these waste products requires water, leading to increased urine production and potentially higher water loss from the body.
Therefore, high-protein diets can have a diuretic effect and increase the need for adequate hydration to compensate for the increased water loss.
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(8 points)
Were the results the same for all the locations in your field study, or different? How do the
areas you monitored compare in air pollution? Based on your knowledge of the area, give a
possible explanation for the differences. Include a table showing the results of your
monitoring of local air quality
Answer:
Answers
The sensors on air quality monitors are built to find particular pollutants. While some rely on satellite images to assess the amount of energy reflected or radiated by the Earth.
What are the primary air contaminants that are being monitored to assess the air quality explain each?The most fundamental is the Ambient Air Monitoring Program, which compiles information on certain pollutants that affect national air quality: Lead (Pb), Particulate Matter (PM), Carbon Monoxide (CO), Nitrogen Oxides (NO2 and NO3), Ozone (O3), and both particles with aerodynamic sizes under 10 micrometres (PM-10)
What does air quality monitoring entail?Monitoring is a process used to gauge a location's level of background air pollution.
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Complete each sentence with the appropriate term or phrase. Some terms and phrases may not be used. male The process in which a reversible modification occurs to a nuclear gene that alters gene expression is known as 75% wild type and 25% dwarf not methylated Monoallelic expression refers to the phenomenon where expressed. genomic imprinting For the igf2 locus it is the allele from the that is not expressed in the progeny. methylated The igf2 locus is unusual in that expression of the locus occurs when the locus is both alleles are female If a female mouse that is homozygous for the mutant igf2 allele is mated to a male who is homozygous wild-type for igf2 then the progeny will be only one allele is 100% wild-type
Answers
The given sentences are related to the topic of gene expression. The appropriate term or phrase to complete the sentence respectively are d. genomic imprinting, h. only one allele is, a. male, c. not methylated, b. 75% wild type and 25% dwarf.
The complete sentences are below:
1. The process in which a reversible modification occurs to a nuclear gene that alters gene expression is known as genomic imprinting. The answer is d. genomic imprinting.
2. Monoallelic expression refers to the phenomenon where only one allele is expressed. The answer is h. only one allele is
3. For the igf2 locus it is the allele from the male that is not expressed in the progeny. The answer is a. male.
4. The igf2 locus is unusual in that expression of the locus occurs when the locus is not methylated. The answer is c. not methylated.
5. If a female mouse that is homozygous for the mutant igf2 allele is mated to a male who is homozygous wild-type for igf2 then the progeny will be 75% wild type and 25% dwarf. The answer is b. 75% wild type and 25% dwarf.
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Fertilizer runoff has a negative impact on aquatic ecosystems because _______. a. it causes plants and algae to grow quickly, suffocating organisms in the water b. phosphorus is not found in nature c. phosphorus is poisonous to living organisms d. living organisms do not require phosphorus in order to survive please select the best answer from the choices provided a b c d
Answers
Fertilizer runoff has a negative impact on aquatic ecosystems because
a. it causes plants and algae to grow quickly, suffocating organisms in the water
What effect can fertilizer runoff have on an ecosystem?When nutrients and other contaminants connected with animal manures and commercial fertilisers are not adequately handled, they can have a harmful impact on plant and animal life (including people). Algal blooms deplete oxygen in surface waters, pathogens and nitrates in drinking water, and the release of smells and chemicals into the atmosphere are just a few of the effects.
Manure and fertiliser nutrients reach lakes and streams via runoff and soil erosion. When soil-test nitrogen (N) and phosphorus (P) levels rise, more plant-available N and P migrate with the water.
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A sarcomere that is at a resting length of 1.7um will generate __________________ force compared to a sarcomere at 2.15um.
Answers
A sarcomere that is at a resting length of 1.7um will generate less force compared to a sarcomere at 2.15um.
Why sarcomere at 1.7um generate less force compared to a sarcomere at 2.15um?The force generated by a sarcomere, the basic functional unit of muscle fibers, is dependent on its resting length. When a sarcomere is stretched beyond its optimal length, it generates less force, while if it is compressed, it generates more force.
At the optimal length, the overlap between actin and myosin filaments is greatest, resulting in the most effective cross-bridge formation and force generation. In this case, a sarcomere at a resting length of 1.7um will generate less force compared to a sarcomere at 2.15um.
Therefore, the optimal resting length of sarcomeres is critical for muscle function, as it allows for the most efficient force production and optimal muscle contraction.
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what is the number one risk factor for skin cancer?
Answers
Answer:
Ultraviolet (which is UV) light from the sun is the main cause for most of skin cancers.
Explanation:
UV light actually damages the DNA (which is genetic material) in skin cells and can cause skin cancer. Happens when the skin is exposed to sunlight over a long duration, or being exposed to sun a lot and getting sunburnt alot.
Answer:
Explanation:
Without doubt, sunlight. People who fear skin cancer should use blocking creams of some sort. Wear a hat with a wide brim. There is also special clothing that you can buy.
Describe at least 4 concepts learned this unit in genetics. Explain why each concept is important. (Digital biology 10th grade)
Answers
Transcription and gene regulatory networks. coding and noncoding RNA mechanisms of action and function. protein synthesis are 4 concepts learned this unit in genetics.
What is genetics?
The study of genes and heredity, or how particular characteristics or traits are passed from parents to offspring as a result of changes in DNA sequence, is known as genetics. A gene is a section of DNA that has the instructions needed to create one or more molecules that support bodily function. A double helix, or corkscrew-shaped ladder, is how DNA is shaped. The bases are pairs of the four building blocks adenine, thymine, guanine, and cytosine, and the two ladder rails are referred to as the backbones. The instructions for constructing molecules, the majority of which are proteins, are included in the sequences of these nucleotides. According to researchers, there are around 20,000 genes in humans.
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Which blood vessel carries the blood from the heart to the lungs for oxygenation?
Answers
The blood vessel that carries blood from the heart to the lungs for oxygenation is called the pulmonary artery.
The pulmonary artery is a major blood vessel that is responsible for transporting deoxygenated blood from the right ventricle of the heart to the lungs, where it will pick up oxygen and release carbon dioxide. This process is crucial for maintaining the proper balance of oxygen and carbon dioxide in the body, which is necessary for our cells to function properly.
As the blood becomes oxygenated in the lungs, it then travels back to the heart via the pulmonary veins, entering the left atrium. From there, the oxygen-rich blood is pumped into the left ventricle, which then sends it throughout the body via the aorta. This continuous process ensures that all of our organs and tissues receive the oxygen they need to perform their functions effectively.
In summary, the pulmonary artery is the blood vessel that carries deoxygenated blood from the heart to the lungs for oxygenation, playing a crucial role in maintaining our body's overall health and functionality.
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