Answer: Hi.... I hope it helps!!
Skin Pigmentation in humans
Explanation: Polygenic inheritance- It is simply a single characteristic which is controlled by more than two genes. Human skin's color is determined by the amount of dark pigment it has which is melanin
. Minimum four genes are involved in the melanin production.
It is a case of continuous variation as the combination of melanin producing allele are responsible for degree of pigmentation
Answer: Geologic time is divided into units. Major changes in the earth's surface or climate and the extinction of species help to divide the time scale into smaller units.
Explanation: Rocks grouped within each unit contain a similar fossil record.
1. Greenhouse gases are compounds that are able to trap heat in the atmosphere, keeping the Earth's surface warmer than it would be if they were not present. The gases are the fundamental cause of the greenhouse effect. Increase in the amount of greenhouse gases in the atmosphere enhances the greenhouse effect which is creating global warming and consequently the climate change. These gases are mainly carbon dioxide; metahne, nitrous oxide, and flourinated gases.
2. Carbon dioxide enters the atmosphere from animals and plants through the process of respiration and the burning of fossil fuels from industries. .
Animals and plants get rid of carbon dioxide gas through respiration. Carbon may also move from fossil fuels to the atmosphere when fuels are burned. Burning of fuels to power factories, power plants, cars and trucks makes carbon to enter the atmosphere as carbon dioxide.
Answer:
Option A is correct (Alfred Wallace).
Explanation:
Option A is correct (Alfred Wallace).
According to the evolution theory all living species are evolved from a simple life source with the passage of time.
Points of natural selection:
- Genetic variation are passed from generation to generation but environment can cause variations too.
- Individuals in species have gene variation which is due to random mutation
- Those who can not adopt to environment can not have their genes pass to next generation.
- Natural Selection is also called as "Survival of the fittest".
