Answer:
there are 4: paracrine signaling, autocrine signaling, endocrine signaling, and synaptic signaling
Explanation:
paracrine:cells that are near one another communicate through the release of chemical messengers
autocrine: a cell signals to itself, releasing a ligand that binds to receptors on its own surface
endocrine:When cells need to transmit signals over long distances, they often use the circulatory system as a distribution network for the messages they send.
synaptic: nerve cells transmit signals. The junction between two nerve cells where signal transmission occurs.
I would say D narrow temperature. Most other planets are too hot or cold to sustain life.
For the answer to the question above, I believe the answer is the<span> phylogenetic species concept</span>.
The key to the phylogenetic species concept is that species must be "diagnosable." In other words, members of the species should share a combination of characteristics that other species don't have. To look for some unique features that define a phylogenetic species, systematic comparisons must be done by paleontologists with other related fossils or living species
