Multicellular organisms must be protected from the external environment. because of this, cells of even the simplest multicellular organisms are arranged to form an external barrier of

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Your answer is epithelial tissue. This tissue is the one that does it part to protect all of the other cells around too or form the external barrier.

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Ans

answer: accepted answer: aquatic animals use the oxygen dissolved in water to carry out respiration. since the amount of dissolved oxygen in water is low as compared to the amount of oxygen in the air, therefore the rate of breathing in aquatic animals is much faster than it is in terrestrial animals.

explanation:

brain development. a child's brain undergoes an amazing period of development from birth to three—producing more than a million neural connections each second. the development of the brain is influenced by many factors, including a child's relationships, experiences and environment.

explanation: