Answer:
Main sequence stars fuse hydrogen atoms to form helium atoms in their cores. About 90 percent of the stars in the universe, including the sun, are main sequence stars. These stars can range from about a tenth of the mass of the sun to up to 200 times as massive.
Stars start their lives as clouds of dust and gas. Gravity draws these clouds together. A small protostar forms, powered by the collapsing material. Protostars often form in densely packed clouds of gas and can be challenging to detect.
"Nature doesn't form stars in isolation," Mark Morris, of the University of California at Los Angeles (UCLS), said in a statement. "It forms them in clusters, out of natal clouds that collapse under their own gravity."
Smaller bodies — with less than 0.08 the sun's mass — cannot reach the stage of nuclear fusion at their core. Instead, they become brown dwarfs, stars that never ignite. But if the body has sufficient mass, the collapsing gas and dust burns hotter, eventually reaching temperatures sufficient to fuse hydrogen into helium. The star turns on and becomes a main sequence star, powered by hydrogen fusion. Fusion produces an outward pressure that balances with the inward pressure caused by gravity, stabilizing the star.
How long a main sequence star lives depends on how massive it is. A higher-mass star may have more material, but it burns through it faster due to higher core temperatures caused by greater gravitational forces. While the sun will spend about 10 billion years on the main sequence, a star 10 times as massive will stick around for only 20 million years. A red dwarf, which is half as massive as the sun, can last 80 to 100 billion years, which is far longer than the universe's age of 13.8 billion years. (This long lifetime is one reason red dwarfs are considered to be good sources for planets hosting life, because they are stable for such a long time.)
Explanation:
I hope this helped!
The answer is B
Here is a small experiment you can do to test this.
<span>
Put a pot of water on the stove and bring it to a boil. Take a dry lid and cover it for a minute, and lift the lid up. What happens?
What should happen is that the water droplets run down the lid and fall back into the pot.</span>
Radioimmunoassay (RIA) is a test that combines radioactive chemicals and antibodies to detect minute quantities of substances in a patient's blood.
In 1959, biophysicist Rosalyn Yalow and physician Solomon A. Berson developed a sensitive method for measuring very small amounts of a substance in the blood called radioimmunoassay (RIA).
Radioimmunoassay (RIA) is a technique that make use of radioisotopes, usually iodine-125, as a tag or label for the detection of antigen. This technique determines the concentration of an antigen based on the competitive binding between radiolabeled and unlabeled antigen for its specific high affinity antibody.
It is very sensitive that it can measure concentrations up to 0.001 μg/ml.
To know more about radioimmunoassay: brainly.com/question/25654772
#SPJ4
Answer:
Explanation:
The production of ATPs for skeletal muscle contraction depends on the conditions that the muscles are exposed to.
In presence of abundant oxygen, to the cells Aerobic respiration-cellular respiration is the most ideal. 32 ATPs and 4 C02 are produced as by-products during the process as by products majorly two C02 from each of the 2 acetyl Co A that enters the kerb's cycle.
Likewise direct phosphoryaltion of ADP to ATP gives 32.0 kj/mol of heat liberated but no C02 was produced. This takes place during chemiosmosis. with 28ATPs produced.
In absence of oxygen, anaerobic respiration of skeletal muscles produced ATPs from glycolysis, heat and 2C<u>02 as products, but not as by-product</u>.Through alcoholic fermentation pathway.
Therefore ,the correct answer is Aerobic respiration, because it gives out C02 which is a by-product, released out of the body as waste from the lungs,and not use up in the body.
