The nutrients get to the cells in a flatworms solid acoelomate body by diffusion process. Flatworms feed primarily on protozoa and bacteria, smaller worms and tiny organisms, dead or alive, that they come across. Based on the species of the flatworms , they also consume plant materials. They rely on diffusion to transport oxygen and nutrients to their internal tissues.
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Answer:
E. that area of the membrane is in the absolutely refractory period.
Explanation:
Refractory period is a period during which neuron cell cannot be stimulated (depolarized). This is why the action potential can only travel in one direction from the neuron body towards axon.
Refractory period occurs because of the inactivation of voltage-gated sodium channels (while action potential is at its peak) which cannot be open for a certain period of time. and membrane cannot be depolarized.
Answer:
C. Traits present in the last common ancestor of a certain group of species under consideration.
Explanation:
Ancestral character traits are the one that is present in the last common ancestor and all of its descendant groups. For example, the presence of the vertebral column is an ancestral trait for all the vertebrate groups such as birds and mammals as it was present in their last common ancestor and is also shared by them.