Answer:
The simplest mechanism by which molecules can cross the plasma membrane is passive diffusion. Passive diffusion is thus a nonselective process by which any molecule able to dissolve in the phospholipid bilayer is able to cross the plasma membrane and equilibrate between the inside and outside of the cell.
What we know about shark and ray fossils comes from bones in rocks from the Cretaceous period in Mexico that left behind, their only hard parts.
<h3>Shark fossils</h3>
The idea of a stingray-like shark may seem like something out of a B-movie. But paleontologists have just reported the discovery of such a creature in Cretaceous rocks in Mexico. This strange shark combines a streamlined body with large, wing-shaped fins, an ancient animal unlike any seen in the fossil record.
<h3>Whose are the fossils?</h3>
Fossils are the remains or traces of living beings that inhabited the Earth in previous geological periods. Fossil remains are parts of animals or plants, such as a bone or some limb or organic remains that have been preserved in some way.
With this information, we can conclude that Fossils are remains or traces of animals and plants preserved in rocks.
Learn more about Fossils in brainly.com/question/22502144
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<span>It is absolutely true that pioneer species can survive on
rocks and minerals. They can survive without the presence of any soil. The pioneer
species produce the food they require by the process of photosynthesis. They
absorb the rain water and salt through their whole body surface. These species
are hardy enough to survive any kind of harsh weather condition. The pioneer species are made to survive real
harsh climates where other species can hardly survive for a single day. </span>
Answer:
Cambium
Explanation:
The thin layer of living cells inside the bark of a tree.