Would you expect motor units to vary in size? If so, which of these structures would probably have the largest ones?
A) No; all motor units are the same size.
B) Yes; a motor unit in the thigh to control leg movements would be the largest one.
C) Yes; a motor unit that controls eye movements would be the largest one.
D) Yes; a motor unit that controls hand movements would be the largest one.
B
You might also like to view...
A population of voles (small mammals) live in a shady forest. Originally, the voles are a light tan color, but then a dark brown coloration arises by a new mutation. The darker voles are harder for predators to see in the leaf litter, thus they are less susceptible to predation. After 10 generations the majority of voles in the population are the dark brown color. In the figure below, the solid red line represents the number of light colored individuals before the mutation and the black dashed line represents the number of dark brown individuals after 10 generations. What type of natural selection are the population of voles going through?
A. Directional selection.
B. Stabilizing selection.
C. Diversifying selection (disruptive selection).
D. Balancing selection.
E. Negative frequency-dependent selection.
A skeleton that consists of a fluid-filled closed chamber that muscles act against is called a(n) ________
a. hydrostatic skeleton b. cytoskeleton c. exoskeleton d. endoskeleton
In DNA replication, a primer is _____
a. what the original DNA strands are called b. an enzyme that breaks the hydrogen bonds between base pairs c. a short piece of nucleic acid that serves as an attachment point for DNA polymerase
d. a molecule that provides the energy for nucleotide attachments e. a regulatory protein that turns on the gene that starts DNA replication
What are responsible for the rapid mobilization of
the immune response after a subsequent attack by a pathogen? a. naive B cells b. naive T cells c. NK cells d. memory cells e. macrophages