Fish poop.
Tropical white beaches get their pearly white color from the excrement of fish far off of the coast which eat coral and other things that reside on the ocean floor. When they eat they swallow some sand into their mouths as well, and process it with the food they just ate. Their stomachs can't really digest the sand, tiny minute rocks essentially, and thus turn their color white. Or the rock forming the sand can be naturally pigmented a whitish tone as well.
Sponges have specialized cells and an endoskeleton, but they lack tissues and body symmetry. ... They include jellyfish and corals, both of which have radial symmetry. All cnidarians have nematocysts, and many are bioluminescent. They may exist in medusa and/or polyp form.
Answer:
abiogenesis
Explanation:
a (not) biogenesis (coming from other life forms)
Biogenesis would mean that it's coming from other life forms,
Natural selection is a part of evolution (what is there to select?)
Variation is also a part of evolution (not related)
ACTH's principal function is to stimulate the cortex (outer layer) of the adrenal glands (located near the kidneys) to secrete a group of steroid hormones called glucocorticoids. Glucocorticoid hormones control the body's use of sugar and also help regulate biological functions during stressful moments