18. Viruses are considered because they can not perform the characteristics of life without a
19. Viruses are made of two basic compounds,
and a
made of protein.
20. A virus infects a cell by injecting
into a cell.

Sweating and breathing is an example of differentiation specialization maintaining homeostasis metabolism

Aristotle classified animals according to their a. habitat and mating behavior c. mating behavior and relatedness b. habitat and physical differences d. physical differences and mating behavior

When new rock is added to an oceanic ridge, the magnetized strips on either side of the ridge are evidence of sea-floor spreading. this is because the rocks on the two sides of the ridge o are equal in width and in polarity are polar opposites oare magnetized vary in width but are equal in polarity