The correct answer is stabilising selection. This is selection that favours an average trait value. It is thought that this sort of selection is very common as traits among most animals do not appear to change drastically over time. Stabilising selection selects against the extreme traits, and leads to a decrease in genetic diversity by favouring the average phenotypes.
Relative dating concerns the dating of fossils by using stratum (layers in the rock) to find the estimated age.
Absolute dating is finding the age of a fossil by using radiometric methods, such as fluorine dating or half-life dating; which is more accurate than relative dating.
2. The evolutionary process through which new species emerge
The products and reactants of each cycle are connected. reactants of photosynthesis (6O2 and C6H12O6) are recycled as products in cellular respiration which produces 6H2O 6CO2 and energy to fuel photosynthesis