Diatoms have cell walls composed of
a. silicon dioxide
b. carbon dioxide
c. chitin

Ocean waves move up and down in circles, but transmit horizontally toward the shore.

Use this diagram of an animal cell to answer the question. where does the first stage of cellular respiration occur? w x y z

1. variations in a population of moths allow for some of its members to be able to adapt to environmental changes. the better adapted of the moths will be able to survive the change and thus prevail as the “fittest” of the species. (a) describe three mechanisms in which variation can occur within a species population. (b) explain which mechanism or mechanisms would be responsible for the survival of a population of peppered moths better than white moths in an environment affected by industrial soot. justify your answer.