The single most important organ system in coordinating our responses to a changing external environment is the ______ system.

A. nervous
B. skeletal
C. muscular
D. endocrine


Ans: A. nervous

Biology & Microbiology

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When potassium ion channels open, which of

the following occurs?

a. potassium ions flow into the axon cytoplasm b. the axon cytoplasm becomes more positively charged c. sodium ions diffuse into the axon cytoplasm d. all of these occur e. none of these occur

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Changing conformation at the active site as a result of binding a substance at a different site is known as ________

Fill in the blank(s) with correct word

Biology & Microbiology

Small circular molecules of DNA in bacteria ____.

A. are plasmids B. are DNA fragments from their main chromosome C. result from the activity of restriction enzymes D. are eventually degraded E. cannot survive outside of the cell

Biology & Microbiology

When would a microbiologist use thioglycolate?

A) when making complex media B) when storing differential plates C) when making defined media D) when storing selective plates E) when storing plates anaerobically

Biology & Microbiology