The answer is a simple radial nervous system.
Echinoderms do not have brains. Around their mouth, they have central rings from which nerves radially run into arms and along the body. Movement is controlled by the branches of those radial nerves.
Diffusion is a spontaneous process in which molecules move with their concentration gradient. For example, if you place food coloring in water, the food coloring will slowly diffuse through the water until the entire solution has been balanced.
Osmosis is specifically the movement of <em>water</em> through a semipermeable membrane - meaning a membrane that can let some substances in but keep others out - and, similar to diffusion, it moves with its concentration gradient. For example, if you place a glucose solution sealed in plastic in water, water will move into the plastic to even out the concentration of glucose in the entire solution because glucose is too large to diffuse freely.
Hope this helped!
The answer is D, metaphase
1) Mutations are caused by changes in nucleotide bases. these altered base formed different amino acid depending upon nucleotide base sequence that code specific amino acid. ... even though some mutations, can have a more effect on amino acid coding, which can affect what kind of proteins are produced.
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