Ques:Answer the following question given this paragraph: When lactose is present, the repressor protein does not bind to the operator. This allows RNA polymerase to bind to the promoter and begin transcription. As a result, the lac genes are expressed, and lactose is digested. Q: When lactose is present in the cell, what allows the lac genes to be expressed? Choices: - concentration of repressor protein - binding of expressor protein - the addition of water - nonbinding of repressor protein A:

Ans:nonbinding of repressor protein
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Ques:Answer the following question given this paragraph: Water and chemical elements that organisms need keep recycling through biogeochemical cycles. These cycles include biotic and abiotic components of ecosystems. Q: Water and chemical elements that organisms need keep recycling through biogeochemical what? Choices: - mutations - levels - effects - cycles A:

Ans:cycles
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Ques:Answer the following question given this paragraph: When done regularly, aerobic activities, such as cycling, make the heart stronger. Other aerobic activities include mowing lawn, shoveling snow and cross country skiing. Q: Cycling, shoveling snow and cross-country skiing are examples of what kind of heart-strengthening activity? Choices: - metabolism - anaerobic - exercise - aerobic A:

Ans:aerobic
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Ques:Answer the following question given this paragraph: Enzymes are proteins that speed up biochemical reactions in cells. Antibodies are proteins that target pathogens for destruction. Q: What are the proteins called that speed up biochemical reactions in cells? Choices: - peptides - hormones - carbohydrates - enzymes A:

Ans:
enzymes
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