One adaptation that is unique to marine mammals is they nurse their young.. The correct option among all the options that are given in the question is the fourth option or the last option or option "d". I hope that this is the answer that you were looking for and the answer has come to your desired help.
Answer:
The endocrine system is a chemical messaging network. Endocrine glands secrete hormones, which are carried by the circulatory system throughout the body. The primary endocrine glands are the pituitary, hypothalamus, pineal gland, thyroid, parathyroid, adrenal, pancreas, ovary, and testis. Hormones maintain homeostasis in the body.
Explanation:
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B is the answer to your question.
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