Cells regulate chemical reactions in order to produce things they need to grow and survive. A( lipids
B( enzymes
c( vitamins
D( carbohydrates

Which of the following explains why a tree is often used as a model to represent the principle of common descent

Which of the following is likely not involved in this example of ecological succession? a) the rotting remains of plants add to the fertility of the soil. b)the soil becomes so fertile that eel grass is replaced by other plant species. c) the roots from plants stabilize the sediment, keeping it in place. d) the concentration of salt becomes so high that all plant life is destroyed.

The model illustrates a process by which a substance is taken up by a cell. which statements describe the process? a. the model shows the process of endocytosis. b. the process shown in the model requires energy from the cell. c. the cell membrane in the model remains intact throughout the process. d. the model shows the process of facilitated diffusion.