The cell membrane has selective permeability and chooses which to pass through. Non polar molecules can pass easily with diffusion, but ions cannot.
Answer 3
Hydrogen is the simplest element in the Universe: it has just one electron orbiting a nucleus of one single proton. It's also the most abundant (helium comes in at a distant second). Immediately after the Big Bang,
You don't have answers, but it protects the cell and filters out things it needs and things it doesn't.
I believe it’s D. Secondary consumers eat plants, if i remember correctly.
The folds increase the surface area of the brain, allowing for more synapses to exist than if it were smooth.