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:
A single gene form different isoforms of protein that result from the alternative splicing of pre-mRNA sequences. one gene many polypeptide hypothesis applies here very well. This whole process helps in proliferating informational diversity and functional capacity of a gene that'll ultimately he;p in gene regulation.
This alternative splicing of pre-mRNA also produces proteomic diversity that result in various development states as well as various disease conditions later.
Answer:
The correct answer is c. production of white blood cells, red blood cells, and platelets.
Explanation:
Hematopoiesis is the formation of all types of blood cellular components and components of plasma like white blood cells, red blood cells, and platelets by hematopoietic system which involves the bone marrow, liver, and spleen.
First, the hemopoietic stem cell divides into common myeloid progenitor and common lymphoid progenitor. From myeloid progenitor RBC, platelets, basophils, eosinophils, neutrophils, and macrophages are formed.
Common lymphoid progenitor gives rise to T- lymphocytes, B- lymphocytes, and natural killer cells. Therefore the correct answer is c. production of white blood cells, red blood cells, and platelets.
