Ques:Q: Down syndrome is caused by having three copies of what, a condition known as trisomy? Read this paragraph and choose the correct option from the provided answers: Chromosomal Disorders Sometimes a genetic disease is not caused by a mutation in a gene, but by the presence of an incorrect number of chromosomes. For example, Down syndrome is caused by having three copies of chromosome 21. This is known as trisomy 21. The most common cause of trisomy 21 is chromosomal nondisjunction during meiosis. The frequency of nondisjunction events appears to increase with age, so the frequency of bearing a child with Down syndrome increases in women over 36. The age of the father matters less because nondisjunction is much less likely to occur in a sperm than in an egg. Whereas Down syndrome is caused by having three copies of a chromosome, Turner syndrome is caused by having just one copy of the X chromosome. This is known as monosomy. The affected child is always female. Women with Turner syndrome are sterile because their sexual organs do not mature. Choices: - genome - variation - DNA - chromosome A:

Ans:chromosome
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Ques:Q: Uranium is an example of a non-renewable resource used to produce what type of power? Read this paragraph and choose the correct option from the provided answers: Some resources can't be renewed. At least, they can't be renewed fast enough to keep up with use. Fossil fuels are an example. It takes millions of years for them to form. We are using them up much more quickly. Elements that are used to produce nuclear power are also non-renewable resources. Uranium, for example, which is rare. Sooner or later, it will run out. Choices: - water - wind - electrical - nuclear A:

Ans:nuclear
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Ques:Q: Dna transcription is controlled by what type of proteins? Read this paragraph and choose the correct option from the provided answers: As shown in Figure below , transcription is controlled by regulatory proteins . The proteins bind to regions of DNA, called regulatory elements , which are located near promoters. After regulatory proteins bind to regulatory elements, they can interact with RNA polymerase, the enzyme that transcribes DNA to mRNA. Regulatory proteins are typically either activators or repressors. Choices: - essential - digested - genetic - regulatory A:

Ans:regulatory
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Ques:Q: What are named for their "spiny skin"? Read this paragraph and choose the correct option from the provided answers: Echinoderms are named for their "spiny skin. " However, the spines aren't on their skin. They are part of the endoskeleton. The endoskeleton consists of calcium carbonate plates and spines, covered by a thin layer of skin. Adult echinoderms have radial symmetry . This is easy to see in the sea star and sand dollar in Figure above . However, echinoderms evolved from an ancestor with bilateral symmetry. Evidence for this is the bilateral symmetry of their larvae. Choices: - arachnids - reptiles - amphibians - echinoderms A:

Ans:
echinoderms
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