The number above the element's symbol is the element's atomic number. Match each element with the number of valence electrons it has.

Anaphase select one: a. is the phase when sister chromatids separate and move to opposite poles. b. involves chromosomes lining up at the equatorial plate. c. occurs before the nuclear envelope breaks down. d. takes place just before cytokinesis. e.

Which structure evolved in cells approximately one billion years ago that allowed for the forming of more complex, multicellular organisms? A) nucleus B) ribosome C) plasma membrane D) golgi apparatus

Which of these is the system of classifying living things into categories, based on physical and chemical features?

Albinism (lack of skin and hair pigmentation) is caused by a recessive autosomal allele. A woman and man, both normally pigmented, have an albino child together. For this trait, what is the genotype of the albino child?

Which of the following are features of a molecular clock? Select all that apply. Select all that apply. It requires knowledge of age of divergence. It uses the rate at which a gene sequence changes to mark evolutionary time.

How does secondary succession differ from primary succession? It begins where no plants have grown. It begins on bare rock or land. Soil nutrients are already in place. Lichens and mosses form soil first.

True of False? The structure of the cell membrane is what allows water and other molecules to move in and out of cells.

Dolphins and fish have similar body shapes. isthis feature more likely a homologous or analogoustrait?

Which of the following is not a phase of gastric secretion? A. cephalic B. gastric C. intestinal D. enterogastric

How are biomes related to ecosystems?