One byproduct of the noncyclic pathway used by early autotrophs was the ________
a. extinction of many early anaerobes
b. all of the choices
c. development of the ozone layer
d. enrichment of the atmosphere with oxygen
b
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The fastest way for organisms to adapt to a changing environment involves _____
A) mutation B) asexual reproduction C) sexual reproduction
Which statement best describes the relationship between a carpel and a pistil?
A. The two terms are merely two names for the same thing. B. A pistil is part of a male component of the flower whereas a carpel is part of a female component. C. A pistil can be composed of either a single carpel (in which case the two terms are synonymous) or of two or more carpels fused together. D. A pistil is a reproductive part of a flower whereas a carpel is a showy vegetative part. E. A pistil is part of the female component of a flower and a carpel is not even a flower part at all.
The rungs of the DNA ladder are formed by base pairs joined by covalent bonds.
joined by covalent bonds. joined by hydrogen bonds. joined by ionic bonds. NOT joined to each other
Which of the following statements regarding enzymes is TRUE?
A. Enzymes decrease the free energy change of a reaction. B. Enzymes increase the rate of a reaction. C. Enzymes change the direction of chemical reactions. D. Enzymes are permanently altered by the reactions they catalyze. E. Enzymes prevent changes in substrate concentrations.