Refer to Animation: Cell Signaling. When cells communicate by the signaling process, one cell produces a that must be received by the on or in the responding cell.

The fruit of a certain plant is sweet and fleshy. the seeds of this plant have a seed coat that is fairly tough. the seeds germinate better if they are exposed to acid, or scarification. what is the most likely type of dispersal for this seed? water animal wind

Is there any species that went extinct in recent years due to natural causes (not caused by human interaction). if so, what caused it?

Which enzymes break down carbohydrates?