How did multicellular animals solve their problem of transport of subs

1.	How did multicellular animals solve their problem of transport of substances?(OR) Write about the evolution we see in the transport system of multicellular animals.
Answer» 1. Early in the evolution, multicellular animals have solved their problem of transport by dissolving majority of the required substances in water and then transporting to various body parts. Ex: Sponges to Heimenthes. 2. Later on the evolution, special fluids like blood and lymph have been developed for the transport of substances within the body. Ex: Insects. 3. In primitive animals, necessary force for transport of these fluids was given by contraction and relaxation of body muscles. These fluids were circulated with in the body cavity. Ex: Earthworm. 4. Later on evolution, for circulation of fluids a closed circulatory system was developed. This consists of heart, blood vessels and blood. Ex: Amphibians, reptiles, aves and mammals.

How did multicellular animals solve their problem of transport of substances?(OR) Write about the evolution we see in the transport system of multicellular animals.

Answer»

1. Early in the evolution, multicellular animals have solved their problem of transport by dissolving majority of the required substances in water and then transporting to various body parts. Ex: Sponges to Heimenthes.

2. Later on the evolution, special fluids like blood and lymph have been developed for the transport of substances within the body. Ex: Insects.

3. In primitive animals, necessary force for transport of these fluids was given by contraction and relaxation of body muscles. These fluids were circulated with in the body cavity. Ex: Earthworm.

4. Later on evolution, for circulation of fluids a closed circulatory system was developed. This consists of heart, blood vessels and blood. Ex: Amphibians, reptiles, aves and mammals.

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