Valves ensure blood flows toward your heart. Vein valves work to bring the blood that flowed down via arteries back up to your heart.
Answer:
a) when cells are small the movement of food and waste can be efficiently handled by the cell membrane
Explanation:
Cells need to get their nutrients and waste in and out of their cell membrane every quickly. Cells are hard workers anyway! The other options also don't make much sense. The cell shape doesn't mean much to their function, and size doesn't impact shape. The cell's internal parts (mitochondria, vacuole, etc) don't support the cell membrane, they have their own functions to focus on. Cells don't work together in tissue but they can interact with each other when needed.
Answer:
the answer would be chromosomes.
Explanation:
A chromosome contains hundreds to thousands of genes.
I recommend you to try analyzing this excerpt in order to compile your own response towards the depicted situation. As for me, there is one stated truth: if someone is really wise and assured that his sphere of occupation is reasonable , this person would never persuade people to believe him/ her and stand on his/her side, because this person does not have doubts about that. Does not matter in what such people believe, they do not have to prove it to anyone who does not shares their views.