Circulation is maintained in the veins by the

Valves

Explanation:

Circulation is maintained in the veins by the valves.

Veins are part of the blood circulation system and blood vessels that transports deoxygenated blood from parts of the body back to the heart. Within the veins are valves (flap like structures) which maintain circulation by ensuring that blood in the veins move in the proper direction toward the heart. Blood that is being transported through the vein usually have low pressure. The valves work by providing pressure to enhance the blood’s movement, and they also disallow backflow of blood as it moves through the body. Most of the veins, especially the ones located in the legs and arms usually have one-way valves.

hey bro i looked it up on google the structure of the eye-spot in euglena viridie, e. ehrenbergii, and phacus pyriyorme is not as franzé haa described it. the so-called “crystal body” and “lens bodies” were not found in any of the individuals of the species examined by me. as earlier observers have stated, the eye-spot consists simply of a mass of pigment granules arranged in a single layer, and probably embedded in a protoplasmic framework, but the latter could not be seen, and its presence was only inferred from the fact that the pigment granules must be held together in some way, thd the eye-spot as a whole is capable of expansion, and that the pigment granules can be separated from each other.

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