D. This is to “proofread” the DNA
Star is a brilliantly glowing sphere of hot gas whose energyis produced by an internalnuclear fusion process. Stars are contained in galaxies. A galaxy contains not only stars, but clouds of gas and dust. These clouds are callednebulae, and it is in a nebula where stars are born. In the nebula is hydrogen gas which is pulled together by gravityand starts to spin faster. Over millions of years, more hydrogen gas is pulled into the spinning cloud. The collisions which occur between the hydrogen atoms starts to heat the gas in the cloud. Once the temperature reaches 15,000,000 degrees Celsius, nuclear fusion takes place in the center, or core, of the cloud. The tremendous heat given off by the nuclear fusion process causes the gas to glow creating a protostar. This is the first step in the evolution of a star. The glowing protostar continues to accumulate mass. The amount of mass it can accumulate is determined by the amount ofmatter available in the nebula. Once its mass is stabilized, the star is known as a main sequence star. The new star will continue to glow for millions or even billions of years. As it glows, hydrogen is converted into helium in the core by nuclear fusion. The core starts to become unstable and it starts to contract. The outer shell of the star, which is still mostly hydrogen, starts to expand. As it expands, it cools and starts to glow red. The star has now reached the red giant phase. It is red because it is cooler than the protostar phase and it is a giant because the outer shell has expanded outward. All stars evolve the same way up to the red giant phase. The amount of mass a star has determines which of the following life cycle paths the star will take.
Answer:
See below
Explanation:
There are several reasons that genetic variation occurs. Some of them are as follows: mutation, random fertilization, recombination event during meiosis etc. The way in which this variation in genetics is distributed is in a continuous way. In case of the human species, it is reported that 85% of all variation is within a certain population, while the remaining 15% of genetic variation is between populations.
Answer:
Explanation:
Species: a group of living organisms consisting of similar individuals capable of exchanging genes or interbreeding.
Population: a particular group or type of people or animals living in a place.
Gene pool: the stock of different genes in an interbreeding population.
Mutations: the changing of the structure of a gene, resulting in a variant form that may be transmitted to subsequent generations, caused by the alteration of single base units in DNA, or the deletion, insertion, or rearrangement of larger sections of genes or chromosomes.
Lateral Gene Transfer: the movement of genetic material between unicellular and/or multicellular organisms other than by the transmission of DNA from parent to offspring (reproduction).
Single-gene Traits: when a trait is linked to one gene-pair that consists of two alleles.
Polygenic Traits: is one whose phenotype is influenced by more than one gene.
The answer is <span>root hairs</span>
