The evolution of the peppered moth evolutionary instance of directional colour change in the moth population as a consequence of air pollution during the Industrial revolution .The frequency of dark-coloured moths increased at that time, an example of industrial mellaniam. Later, when pollution was reduced, the light-coloured form again predominated. Industrial melanism in the peppered moth was an early test of Charles Darwin natural selection in action, and remains as a classic example in the teaching of evolution.
Photos means light
tropos means turning
phototropism means turning towards the light
answer is A
(gravotropizom is like gravity, if you hold that kind of plant sideways, it will try to turn sidewyas, dunno thigmatropism, helio tropizom is turning toward the sun (but ther are other light sources other than sun))
I think it is C An increase in the activity of nitrogen-fixing bacteria but don’t hold me to that I’m not sure