How might biotic and abiotic factors have affected the tortoises that Darwin observed on the Islands

Some Abiotic factors are water, soil, light, temperature. These are non-living things that the tortoises will interact with in the enviornment. These can affect them for example if there is an abundance of water and light then the tortoise population can expand. However if there is too little or too much of these factors then the population will decrease. Biotic factors are plants, animals, bacteria and Protists. These are the living things the tortoises will interact with in the enviornment. Biotic factors can affect them for example if there are too many preditor animals for the tortoises, then their population will be very low and a lot of them will die.

Explanation:

the menstrual cycle – higher tier. negative feedback mechanisms affect the production of hormones in the menstrual cycle. oestrogen also stimulates the release of lh (luteinising hormone) from the pituitary gland, which in turn controls the production of progesterone.