Step 1: Understanding the male reproductive system. The male reproductive system is primarily responsible for the production of male gametes (sperm) and hormones like testosterone. The testes are the key structures where spermatogenesis (the production of sperm) occurs.
Step 2: Spermatogenesis in the testes. - Spermatogenesis occurs in the seminiferous tubules within the testes. - These tubules are lined by germ cells and Sertoli cells, which aid in the development of sperm.
Step 3: Explanation of other options.
Prostate gland: Produces seminal fluid that nourishes and protects sperm.
Seminal vesicles: Contribute to the production of seminal fluid.
Epididymis: Stores and matures sperm but does not produce it.
Hence, the correct answer is (D) Testes.
Given, the function \( f(x) = \frac{a^x + a^{-x}}{2} \) (\( a > 2 \)), then \( f(x+y) + f(x-y) \) is equal to