Id say this is more of a biology question or even a psychology question , well its not a question at all but the endocrine system is a collection of glands that secrete hormones direct to the blood system (circulatory system) to be sent to the desired / target organ , an example of a gland could be the pituitary gland (located towards rear of brain)
Answer:
I would say the answer is the wave of 21.000Hz
Explanation:
Because it has more frequency, and as more frequency you add, the time or longer period also increases.
[two waves] pass a point [every second]... The answer is in the question (B)
Since force is mass*acceleration,
F = 70kg * 9.8 m/s