Ques:Q: Most of the heat that enters the mesosphere comes from where? Read this paragraph and choose the correct option from the provided answers: There are very few gas molecules in the mesosphere. This means that there is little matter to absorb the Sun's rays and heat the air. Most of the heat that enters the mesosphere comes from the stratosphere below. That's why the mesosphere is warmest at the bottom. Choices: - Earth's surface - Exosphere - Troposphere - the stratosphere A:

Ans:the stratosphere
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Ques:Q: Clearing land for agriculture and development is a major cause of what negative result? Read this paragraph and choose the correct option from the provided answers: Clearing land for agriculture and development is a major cause of habitat destruction. Within the past 100 years, the amount of total land used for agriculture has almost doubled. Land used for grazing cattle has more than doubled. Agriculture alone has cost the United States half of its wetlands ( Figure below ) and almost all of its tallgrass prairies. Native prairie ecosystems, with their thick fertile soils, deep-rooted grasses, diversity of colorful flowers, burrowing prairie dogs, and herds of bison and other animals, have virtually disappeared ( Figure below ). Choices: - water destruction - human destruction - mineral destruction - habitat destruction A:

Ans:habitat destruction
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Ques:Q: Most chromosomal disorders involve which chromosomes? Read this paragraph and choose the correct option from the provided answers: Most chromosomal disorders involve the sex chromosomes. Can you guess why? The X and Y chromosomes are very different in size. The X is much larger than the Y. This difference in size creates problems. It increases the chances that the two chromosomes will fail to separate properly during meiosis. Choices: - autosomes - ribosomes - protosomes - sex chromosomes A:

Ans:sex chromosomes
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Ques:Q: How many pairs of chromosomes are found in human cells? Read this paragraph and choose the correct option from the provided answers: Human cells have 23 pairs of chromosomes, and each chromosome within a pair is called a homologous chromosome . For each of the 23 chromosome pairs, you received one chromosome from your father and one chromosome from your mother. Alleles are alternate forms of genes found on chromosomes. Homologous chromosomes have the same genes, though they may have different alleles. So, though homologous chromosomes are very similar, they are not identical. The homologous chromosomes are separated when gametes are formed. Therefore, gametes have only 23 chromosomes, not 23 pairs. Choices: - 25 - 24 - 13 - 23 A:

Ans:
23
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