Natural selection can only occur because of a variety in a population. Natural selection refers to environmental factors that affect a population and causes some of the population to have more surviving offspring than others. An example is a giraffe with a longer neck will be more likely to survive and reproduce (as it can gather more food from taller trees)
Answer:
Neurological signals sent from fear responses in an organism tell the cell to stop. The cell's DNA has been damaged somehow. The cell's DNA was replicated incorrectly.
Explanation:
All the three options given can cause checkpoint genes to interrupt cell division.
Checkpoint genes are transcription genes that control cell cycle and sense defects during cells processes like DNA replication, segregation e.t.c and create response till the defects is repaired in the DNA. The important of checkpoint is that it ensure enough nutrients are available to support for division, ensure that the DNA has not been damaged, ensure that cells DNA is copied correctly and make sure cells have enough RNA for their protein synthesis.
Checkpoints genes can interrupt cell division if the dna is damaged, Dna is copied incorrectly and neurological signal sent from fear responses in an organisms tell the cells to stop.
Answer:
Due suitable environment and high productivity.
Explanation:
More fish are supplied by fish farming rather than from traditional because farms are build in order to harvest more fish by providing suitable environment to the fish. In transitional ways, fish are caught in nets from the rivers by local people for theirselves and the extra will sold in the market. In rivers there are less number of fish which does not meet the requirements of people so that's why commercial farming of fish can be done.
Light initially enters the eye through the cornea, it protects the eye and helps to focus light rays into the retina at the back of the eye. The passage of light continues through the pupil which looks like a black circle in the centre of the eye. The pupil is not a structure itself but helps to control the amount of light entering the eye. The iris surrounds the pupil, is the coloured part of the eye. It is a ring of muscles which expand or contract to change the size of the pupil and control the amount of light. The optic nerve carries the visual information from the retina to the primary visual cortex. The optic nerve exits the eye at the back of the retina, the same point where blood vessels enter and exit the eye.
