Small structures used for removing debris from the surface of sea stars are:
a. madreporites.
b. spines.
c. tubercles.
d. pedicellariae.
e. the dermal gills.
D
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PCR produces
A. DNA fragments of all possible sizes. B. DNA fragments that are one nucleotide larger than the next fragment. C. DNA fragments of a particular size. D. DNA fragments of increasing size. E. DNA fragments that are one nucleotide larger than the next fragment AND DNA fragments of increasing size.
The maximum number of individuals of a species that a given environment can sustain indefinitely defines ____
a. the carrying capacity of the environment b. exponential growth c. the doubling time of a population d. density-independent factors e. density independent factors
What situation results from a postfertilization barrier to reproduction?
A) mutations in genes that control development B) offspring that fail to develop C) mechanical isolation of a species D) gamete incompatibility
Which of the following is not a structural motif associated with transcriptional regulation?
A) CpG motif B) helix-turn-helix C) zinc finger D) leucine zipper E) helix-loop-helix