Hello again!
If plants are purebred, then they are homozygous. This means that they have the exact same genes in one pair: for example, AA. If they are both purebred, then the dominant gene will win out every time. The answer for this question, then, would be D. Here is a diagram to help you!
Answer:
overreacts to an antigen
Explanation:
Allergies to substances are as a result of immunological dysfunction.
Given that,
The speed of a wave, v = 200 m/s
Wavelength, 
We need to find the frequency of this wave. The relation between wavelength, frequency and the speed is given by :

So, the frequency of this wave is 100 Hz.