10. What is a trophic cascade? a. when predators increase the density and/or behavior of their prey and thereby enhance
survival of the next lower trophic level.
b. when predators limit the density and/or behavior of their prey and thereby limits survival
of the next lower trophic level.
c. when prey limit the density and/or behavior of predators and thereby enhance survival of
the next lower trophic level.
d. when predators limit the density and/or behavior of their prey and thereby enhance
survival of the next lower trophic level.

Which of these is true of the cytoplasm of an unfertilized egg? a. it is an unevenly distributed mixture of mrna, proteins, organelles, and other substances. b. it does not contain substances that are important in directing development. c. these substances are supplied by the sperm. d. it does not contain substances that are important in directing development. e. development is directed solely by the surrounding cells. f. it is a homogeneous mixture of mrna, proteins, organelles, and other substances. g. it does not contain substances that are important in directing development. h. these substances are produced by the dna of the fertilized zygote.