In an eight-cell embryo of an organism, the cells of the upper tier are aligned over the cells of the lower tier at a slight angle. which organism is it likely to be? the choices are the following: earthworm. . starfish. . sea cucumber. . sea urchin.

Groups of organisms with low biotic potential, such as gray whales, that produce at most one offspring every other year a) are r-selected b) are k-selected c) are not subject to density-dependent limiting factors d) show the initial stages of the extinction process e) have escaped from the processes of natural selection and adaptation

Describe characteristics of a good respitory surface

Produce proteins by following coded instructions that come from the nucleus of the cell.