Human embryos have a developmental stage during which they have a tail and pharyngeal pouches (those pouches develop into gills in fish). How can we explain these characteristics of human embryos?
A) Human embryos need a tail and gills to breathe during development in the placenta.
B) Human embryos spend time in the water where tails and gills are useful.
C) Human embryos share a common ancestor who had gills.
D) Both A and B are correct.
C
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Mutagenic chemicals that ____ and are incorporated into DNA or RNA during synthesis are called base analogs
a. resemble nucleotides b. resemble genes c. resemble amino acids d. cause deletion mutations e. cause frameshift mutations
Photosynthesizing plants rely on water to
a) replace electrons that are excited by light energy and passed from molecule to molecule down and electron transport chain b) replenish oxygen molecules that are lost during photosynthesis c) provide the protons necessary to produce chlorophyll d) concentrate the beams of light hitting a leaf, focusing then on the reaction center e) serve as a high-energy electron carrier
Rationalizing is a _____ form of coping.
A. emotion-focused B. problem-focused C. primary appraisal D. juvenile
It has been suggested that global warming could be halted by fertilizing the oceans to increase the growth of algae. How might this affect the greenhouse effect?
A) Algal photosynthesis would use up more CO2, which traps heat. B) Algal photosynthesis would produce more O2, which blocks light. C) Algal photosynthesis would be inhibited by the addition of fertilizer. D) Algae photosynthesis would use heat in place of photons.