Compare and contrast a cell membrane and cell wall.

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Explanation:

a cell wall is only found in plant cells to provide protection and structure a cell membrane is found in plant and animal cells and its basically a filter and decids what gets in and out of the cell

answer: the blood-brain barrier is a layer of specialized membranes and cell processes designed to keep undesirable substances from passing from the bloodstream into the precious tissues of the brain. while the blood-brain barrier does keep most bad things out of the central nervous system, it is not impermeable.

explanation:

c) 50% there are four chromosomes. after crossing over, 2 of the four have been changed. that means any gamete has a 2 in 4 chance or 50% chance of receiving the mutated chromosome.