The proportion of the air we breathe accounted for by oxygen is approximately ___%.

A. 21
B. 1
C. 5
D. 50
E. 78


A. 21

Biology & Microbiology

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Each of two daughter cells that result from the normal mitotic division of the original parent cell

contains ____.

a. the same number of chromosomes but different genes than the parent cell b. the same number of chromosomes and genes identical to those of the parent cell c. half the number of chromosomes but different genes than those of the parent cell d. half of the number of chromosomes and genes identical to those of the parent cell e. twice the number of chromosomes and genes identical to those of the parent cell

Biology & Microbiology

Select the molecule that contains the least stored chemical energy:a

ethyl alcohol. b. pyruvate. c. glucose. d. lactate. e. oxygen.

Biology & Microbiology

Which is a major group of enzyme-linked receptors?

a. G proteins b. ion channels c. tyrosine kinases d. phospholipases e. adenylyl cyclases

Biology & Microbiology

Where would the highest-energy electron be found in an atom of hydrogen?

a. in the second spherical orbital b. in the dumbbell-shaped orbital of the y axis c. in the spherical orbital closest to the nucleus d. in the dumbbell-shaped orbital of the z axis e. in the dumbbell-shaped orbital of the x axis

Biology & Microbiology