AP BIOLOGY

Detailed explanation-1: -There are four basic categories of chemical signaling found in multicellular organisms: paracrine signaling, autocrine signaling, endocrine signaling, and signaling by direct contact.

Detailed explanation-2: -Not all cells respond to the same signals, and one cell may respond to the same signal in different ways. Different cells can respond in different ways to the same signal. The way a cell responds to a particular signal depends on the signal transduction pathways present in the cell.

Detailed explanation-3: -Communication between and within cells There are two kinds of cellular communication: communication between cells is called intercellular signaling, and communication within a cell is called intracellular signaling.

Detailed explanation-4: -The three main ways for cells to connect with each other are: gap junctions, tight junctions, and desmosomes. These types of junctions have different purposes, and are found in different places.