Many times species are composed of networks of distinct populations called metapopulations. When do metapopulations occur?
A. When suitable habitat is patchily distributed and separated by areas of unsuitable habitat
B. When a population is large and uniformly distributed
C. When a population in poor habitat continually sends out dispersers to bolster populations in better habitats
D. When a population in a better habitat does not send out colonizers into less suitable habitats
Answer: A
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In a nucleotide, the sugar is bonded to a
A. sugar. B. codon. C. salt. D. base and phosphate.
The ideal Christmas tree has a conical shape. The top of the tree is pointed and narrow, with clear apical dominance, and the bottom of the tree is wide, with extensive lateral branching
Certain evergreen species are suitable for use as Christmas trees because they have this shape normally and thus require little pruning or training as they grow. For example, spruces and firs are often grown as Christmas trees, whereas yews and longleaf pines are not. Based on this information, spruces and firs are likely to have A) high levels of auxins near the top and low levels of cytokinins at the bottom of the tree. B) high levels of auxins near the top and high levels of cytokinins at the bottom of the tree. C) low levels of auxins near the top and high levels of cytokinins at the bottom of the tree. D) low levels of auxins near the top and low levels of cytokinins at the bottom of the tree.
second part of small intestine
What will be an ideal response?
Which statement is true about speciation on island archipelagos?
A. Speciation is slow because it depends on emigration from the mainland. B. Most speciation occurs allopatrically. C. Speciation by polyploidy is most common. D. Species clusters are less common. E. Ecological competition may cause new species to go extinct, slowing speciation.