How do the muscles in your arm extend your arm outward?
A. The muscles in your arm push on the bones, causing your arm to extend.
B. The muscles in your arm relax, and the tendons pull the arm straight.
C. The top half of your bicep wraps around underneath the elbow like a rope over a pulley. When it contracts, the arm is pulled out straight.
D. Some muscles in your arm relax, and others contract, pulling the arm straight.
Answer: D
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What must be true when electrons are passed between protein complexes?
a. Electrons are directly passed from one complex to the next by physical contact. b. The oxidized electron carrier passes on the electron and becomes reduced. c. A proton is translocated to the inner mitochondrial space. d. The matrix decreases in pH. e. The reduced electron carrier passes on the electron and becomes oxidized.
Lake Ontario is home to a species of catfish with green and brown phenotypes, of which the green variant is more abundant, and the brown variant is more susceptible to predation. An angler accidentally releases brown catfish into a nearby pond where only green catfish had previously existed, and the brown catfish quickly supplant the native green catfish population there. The exact reason for the brown catfish’s newfound success is unknown, but it is possible that they are better able to hide from predators in the brown silt and thicker foliage that exists in the pond. What principle would this demonstrate?
a. directional selection b. absolute fitness c. relative fitness d. diversifying selection
The protein that helps make vertebrate skin tougher and more waterproof is:
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The distribution of hippopotamuses in muddy shallows is an example of ____ distribution.
A. clumped B. random C. uniform D. constant E. homogeneous