The answer would be: C) sexual selection.
Sexual selection happens where one of the individuals choose the partner to sex based on some criteria. In this case, the ability to have a beautiful bower will determinate the ability of the bird to have sex and produce offspring. The criteria are not limited to visual. It could be diverse in other cases, like a deeper croak in frog
Answer:
Option A
Explanation:
Thyroid is primarily caused by lack of iodine but there are other reasons as well that lead to increased size of the thyroid gland. Some of these reason is
a) over- or underproduction of thyroid hormones
b) Nodules in the glans
Some times, due to overstimulation immune system itself attack the thyroid gland thereby producing excess thyroxine and hence causing the thyroid to swell
Thus, Option A is correct
A parasite invades the species and causes its population to decline because a biotic factor is a living factor that affects a species
