Given, the function \( f(x) = \frac{a^x + a^{-x}}{2} \) (\( a > 2 \)), then \( f(x+y) + f(x-y) \) is equal to
There are series of events that happen in the development of plants after their fertilization process to form a fruit from a diploid zygote. The four different developmental steps that occurs during post fertilization are: