Which interval is classified as a “period” in the geologic time scale rather than an “era”?
a. Mesozoic
b. Proterozoic
c. Carboniferous
d. Cenozoic
e. Paleozoic
ANSWER: c
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Because oxygen is more electronegative than hydrogen, the water molecule is:
A. hydrophobic. B. hydrophilic. C. nonpolar. D. ionic. E. polar.
Lignified, tube-like structures that branch throughout the body of some plants, conducting water and
solutes, are called ____.
a. vascular tissues b. apical meristems c. root systems d. rhizomes e. shoot systems
Internal fertilization is more advantageous than external fertilization because:a
internal fertilization permits cross-species fertilization.
b. internal fertilization is more open to chance. c. internal fertilization produces a motile egg. d. internal fertilization increases the life span of gametes. e. internal fertilization provides a protective environment for gamete fusion.
The human tailbone is an example of a vestigial structure. A vestigial structure is one that is present in an organism but that has a reduced size and little or no function. For example, the human tailbone is tiny and plays no role in balance or locomotion. In contrast, the tailbone in other animals, such as dogs and cats, is prominent and serves a function. Vestigial structures are used to support the theory of evolution. What type of evidence do vestigial structures represent?
A) fossil evidence B) molecular biology C) comparative anatomy D) biogeography