Which of the following mechanisms is not used to propel lymph through lymphatic vessels? a. gravity b. small heart-like pumps c. the milking action of muscles d. pulmonary motion

Which of the following is the earliest era of earth's geologic time scale? cenozoic mesozoic precambrian paleozoic

The embryos of a bird, a reptile, and a mammal are similar in appearance. how does comparing the physical appearance of embryos of different species support the theory of evolution? a. it shows that these organisms share a common ancestor. b. it provides evidence that these organisms eat the same foods.c. it shows that these organisms share the same habitat.d. it provides evidence that these organisms suffered a genetic mutation.

Which of the following molecules can be broken down into simple sugars? a. nucleic acid b. protein c. lipid d. carbohydrate