What is the main way that a beaver can be a keystone species in its ecosystem?
a) it can serve as a food source
b) it can introduce diseases into the ecosystem
c) it can act as a predator
d) it can provide aquatic habitat
Ans: d) it can provide aquatic habitat
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The rate of aerobic respiration in plants depends upon the
a. availability of oxygen. b. lifestyle stage. c. temperature. d. all of these
Two species of birds compete for the same size of seed eventually develop different beak sizes that allow them to compete for different sizes of seeds. What has occurred?
a. competitive exclusion only b. character displacement only c. directional selection only d. competitive exclusion and character displacement e. directional selection and character displacement
The human has __________ sets of autosomal chromosomes. What will be an ideal response?
Scientists are attempting to make a chicken look like a dinosaur ("dino-chicken") by using drugs or proteins to turn on certain homeotic genes in somatic cells during the development of a chicken embryo. If the scientists are successful in creating both
male and female "dino-chickens," and then the "dino-chickens" mate, what type of offspring would the two "dino-chickens" have? A) a male or female "dino-chicken" B) a male or female normal chicken C) You can't know for sure because of random fertilization. D) You can't know for sure because it depends on whether the modified homeotic genes are dominant or recessive.