The micro tubes that form prophase and control chromatids are called spindle fibers.
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:
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Answer: There is a lot
Explanation:
You're made partly of carbon, so is clothing, furniture, plastics and your household machines. There is carbon in the air we breathe. Diamonds and graphite are also made of carbon.
The part of a flowering plant that develops into a seed is the ovule.
When pollen grains land on the stigma of the correct species, they germinate. A pollen tube grows through the tissues of the flower until it reaches an ovule inside the ovary.
The nucleus of the pollen grain (male gamete) then passes along the pollen tube and joins with the nucleus of the ovule (the female gamete). This process is called fertilization.
After fertilization, the female parts of the flower develop into a fruit. The ovules become seeds and the ovary wall becomes the rest of the fruit.
The cytokine describes the group of proteins such as interferons and interleukins that regulate cell communication, mainly produced by the immune system in normal and pathological conditions.
<h3>What is a cytokine?</h3>
They are messenger molecules with a glycoprotein structure, whose lifetime is short and generally secreted in cascades.
They are produced by different activated cells, responsible for innate and/or acquired immunity, and regulate the immune and inflammatory response.
Therefore, we can conclude that the cytokine describes the group of proteins that regulate cell communication, mainly produced by the immune system in normal and pathological conditions.
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