Number of protons - 3
number of neutrons - 4
number of electrons - 3
The physiological process which explains the principles is mitosis b.
Answer:
Environmental factors can influence natural selection because they can increase or decrease the amount of genetic variation in a population.
Explanation:
Natural selection is a process that involves the survival of species through changes in the expression of their genes, making possible the process of adaptation to environmental changes. It is one of the explanations for the biological evolution of species.
The second premise, necessary for natural selection to be possible, implies the existence of a variability (genetics) of traits among individuals in a population.
The other premises of natural selection are the faculty of traits to be inheritable and that genetic variability should lead to reproductive success and survival.
- <em>The other options are not related to the process of natural selection, since it is not possible for natural selection to increase or decrease the number of chromosomes, in addition to the fact that genetic variability must be observed in a population, not in a single individual, to be considered natural selection </em>
The Precambrian era envelopes the major bulk of the history of the Earth, beginning from the creation of the planet approx 4.5 billion years ago and terminating with the origination of composite, multicelled forms of life approximately 4 billion years after.
The Precambrian refers to the earliest of the geologic ages that are signified by the distinct layers of sedimentary rock. The Earth was about more than six hundred million years old when life started. The planet had cooled down from its native molten state, creating a solid crust and oceans formed by water vapor in the atmosphere.
At about three billion years ago, the atmosphere of the Earth was virtually devoid of oxygen. At approximately 2.4 billion years ago, oxygen was discharged from the seas as a waste product of photosynthesis by cyanobacteria. The levels of the gas slowly raised, attaining about 1 percent around two billion years ago.
Approximately 800 million years ago, the levels of oxygen attained about 21 percent and started to breathe life into more composite species. The oxygen-rich ozone layer was also created, protecting the surface of the Earth from the harmful solar radiation.