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.
Normally a 10× drop for each trophic level, so I'd say 2,000 kilocal.
TRUE. the placenta develops in the mother's uterus during pregnancy. The structure provides oxygen and nutrients to the growing baby and removes waste products from the babys blood
Answer:
Explanation:
rna is produced in the transcription stage of protein synthesis whereby complementary base pairing occurs
Hello!
For the complementary strand of DNA, 36 Thymine bases and 24 Guanine bases would complete the proper base pairing.
This is given by the concept of complementarity. A base in DNA has complementarity with only one other base. This complementarity is produced by hydrogen bond interactions.
For DNA, Adenine couples with Thymine and Cytosine couples with Guanine. So the 36 adenine bases will couple with 35 thymine bases, and so on.
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