To calculate the frequency of an electromagnetic wave, you need to know the speed of the wave which you already know as 186000 miles per second and its
a. refraction intensanator
b. amplitude divisor coefficient
c. intensity lumenous
d. wavelength

D. Wavelength

Explanation:

Frequency is the number of waves that pass through a given point in a given amount of time. You've been given the speed and amount of time, all that's remaining is the wavelength.

acid rain does not usually kill trees directly. instead, it is more likely to weaken the trees by damaging their leaves, limiting the nutrients available to them, or poisoning them with toxic substances slowly released from the soil. the main atmospheric pollutants that affect trees are nitrates and sulphates.