In an anatomy lab, you are shown a skeleton from a sea cucumber, with its internal calcium-rich spines. You would call this a(n)
A. exoskeleton.
B. hydrostatic skeleton.
C. gastrovascular cavity.
D. endoskeleton.
E. vascular canal.
D. endoskeleton.
You might also like to view...
The function of a protein is dependent upon the shape into which the chain of amino acids folds. Many non-covalent interactions are responsible for maintaining the protein's shape. Assume you have isolated a protein from an organism in its proper shape
and you have treated it with an enzyme that selectively targets and breaks only the peptide bonds in the proteins. Would the protein retain its shape under these conditions? A. Yes; once the shape of a protein is formed, the peptide bonds are unnecessary. B. Yes; the non-covalent interactions are stronger than the peptide bonds. C. No; while the non-covalent bonds determine the shape of a protein, the peptide bonds are required to hold the amino acids together. D. Yes; but the shape would be affected to a greater extent by changes in temperature.
The short, branched extensions that receive input from other neurons are the
A. dendrites. B. axons. C. synapses. D. nuclei. E. nodes of Ranvier.
Fatter sociable weaver birds spend more time foraging where they are vulnerable to predation, are more attractive to
predators, and are less likely to escape an attack. Conversely, thin birds risk starvation. Therefore, sociable weaver of an intermediate weight have a selective advantage. This is an example of ____ selection.
a. frequentb. directional c. disruptive d. stabilizing e. mutational
Familial hypercholesterolemia is a disease that is incompletely dominant. This means that
A. the dominant allele completely masks the recessive allele, so the dominant phenotype is displayed. In the case of familial hypercholesterolemia, heterozygotes will have extremely high levels of cholesterol, identical to those seen in homozygous dominant individuals. B. the dominant allele does not fully mask the recessive allele, so an intermediate phenotype is displayed. In the case of familial hypercholesterolemia, heterozygotes have moderately higher levels of cholesterol compared to normal. C. the dominant allele is equally dominant with a second (or third) dominant allele, so both phenotypes are displayed. In the case of familial hypercholesterolemia, heterozygotes have moderately higher levels of cholesterol compared to normal. D. multiple alleles exist for this trait, so multiple phenotypes are possible. In the case of familial hypercholesterolemia, heterozygotes can have a range of cholesterol levels depending on which combination of alleles exists.