Answer:
The correct statement concerning the cell membrane lipid molecules is that "energy is not expended during diffusion" (Option d)
Explanation:
Biological membranes are formed by two lipidic layers arranged with their hydrophilic polar heads facing the exterior and the interior of the cells, and their hydrophobic tails against each other. Membranes are fluid, which means that molecules that form it have the capability to move through it.
Lipids can easily change places with other neighbor lipids by <u>lateral diffusion</u> in the same layer. This is passive diffusion, which means that it does not need energy to happen.
Lipids can also diffuse transversally to the other layer, but this kind of movement is not as easy as lateral diffusion.
There are also other lipidic movements as rotational diffusion that imply the rotation of the molecule.
Through this lipidic bilayer, there is also a passive transport of some particles from one side of the cell to the other which happens because of concentration differences.
Answer:
Xylem carries water and minerals from the roots to the leaves. Whereas, phloem carries the food prepared by the leaves to different parts of the plant.
Explanation:
Answer:
Evolution provides evidence as to how animals such as birds are related to much older animals. Over time, species evolve and adapt to their surroundings to suit their habitat. Thus many different species pop up. This all doesn't happen in the blink of an eye, though.
A vestigial organ, something that has yet to fall prey to evolution, but no longer serves a purpose, or the purpose it used to serve.
The correct answer is A. This is because undeveloped meaning they don't have access to any of the other offered answers
