Answer:
a. allow a variety of molecules to cross the cytoplasmic membrane
Explanation:
The cells have different molecules in its membrane. As a membrane the main function of it is to regulate the income and outcome of substances that the cell needs or the cell has like some wastes.
Some of these molecules can be some proteins like the permeases, that is going to regulate the solutes that can enter the cell, but since they are non specific, that means that can not make the difference among one carbohydrate and another (as an example).
Answer: A.
Explanation:
Cells generally have a relatively short lifestyle in that they grow, divide and then die off. This is not the case with cancerous cells as those ones mutate and then multiply such that they eventually form a tumor.
Looking at the graph, most of the cells are remaining at a lower or manageable number because they are dying off. Cell A on the other hand is simply increasing in number which means that it is a cancerous cell as it is increasing its number by mutating instead of dying off like other cells would.
Explanation:
Classification systems function in order to organize a group of organisms into smaller groups according to some kind of logic. For example, the most used classifications system in biology is the phyllogenetic, which classifies living beings according to their evolutive affinity.
In the other hand, a dichotomous key is a "guide" used by biologists when they need to indentify an individual. It is organized in several steps regarding some key characteristics in order to guide you to which species/genus/family your individual belongs to. A dichotomous key never provides any kind of trustworthy phyllogenetic information, and should be understood only as a tool.
The immune system, and the excretory system
(Honestly, all of them work to keep us 'healthy', but I believe these are the ones you're looking for)
A chromosome is made of both one DNA molecule wound around small protein molecules whereas DNA is just one large molecule called deoxyribose nucleic acid.
