Life probably would never have emerged on Earth if
the ancient atmosphere had been the same as the
present one in regard to
a. carbon dioxide.
b. hydrogen.
c. oxygen.
d. nitrogen.
e. carbon monoxide.
Answer: c
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In a grasshopper, how does ion composition of pre-urine compare to hemolymph?
A) Pre-urine is significantly higher in osmolarity (especially with respect to Na+ and K+). B) Hemolymph is higher in osmolarity, conserving its Cl-. C) Pre-urine is similar to hemolymph in ion composition. D) The protein pumps and channels of the Malpighian tubules concentrate Cl- in the pre-urine.
Which environment is ideal for plant cells, and which is best for animal cells?
a. isotonic for plant cells, and hypertonic for animal cells b. isotonic for plant cells, and hypotonic for animal cells c. hypotonic for plant cells, and isotonic for animal cells d. hypotonic for plant cells, and hypertonic for animal cells
Hershey and Chase demonstrated that when the bacteriophage T2 infected its host cell, the ________ is injected into the host but the ________ remained outside.
Fill in the blank(s) with the appropriate word(s).
Which kind of vessel has the lowest blood velocity?
A) artery B) capillary C) venule D) vein