Changes within a gene pool occurring from generation to generation is called microevolution. Allele frequencies in a population may change due to gene flow, genetic drift, natural selection and mutation. These are referred to as the four fundamental forces of evolution.
C.
Depending upon the type of energy detected by receptors , they can classified into many groups but you need for so I'm going to write here only four with their functions
1. Thermoreceptors: they detect changes in temperature
2. Chemoreceptors: they detect chemicals dissolved in body fluid medium surrounding them.
3. Mechanoreceptors: they detect sound , motion , position in relation to gravity.
4. Photoreceptors: they detect visible and ultra violet light!
Hope so it would help!
Solar energy and radiation