The sun is the ultimate source of energy and the process is Photosynthesis.
Answer:
That hemoglobin is the substance that transports oxygen..
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.
Answer:
during the Cambrian Period of the Paleozoic Era.
Explanation:
The Paleozoic is the earliest era (of three) of the Phanerozoic Eon and is composed of six geologic periods: the Cambrian, Ordovician, Silurian, Devonian, Carboniferous, and Permian (in that order from earliest to the latest). Fish first appeared about 530 million years ago during the Cambrian explosion.