The composition of a star is abundant in hydrogen and helium, both of which are two of the lightest elements. Because they are very light, they are usually unstable. To becomes stable, hydrogen atoms spontaneously combine with each other through a radiation process called nuclear fusion, to yield helium atoms. This process requires very high energy in the form of heat. Therefore, these lighter elements are burned in order to keep the star alive with energy.
Therefore, the answer is D.
Ans.
Steroids are defined as active organic bio-molecules, having four rings with a specific molecular configuration. Steroids play role in two major functions: as hormones or signaling molecules and as structural components of plasma membrane.
Examples of steroid hormones are estrogen, progesterone, and cortisol. Thus, the correct answer is 'option b). they serve as chemical messengers.'
Here is one possible answer:
Do allergen-free pillows cause fewer germs to grow
ransfer RNA (tRNA) – a type of RNA that is folded into a three-dimensional structure. tRNA carries and transfers an amino acid to the polypeptide chain being assembled during translation. translation – the process in which a cell converts genetic information carried in an mRNA molecule into a protein.
Tropical rainforest is a biome which is warm and wet, with little seasonal variation in temperature and frequent precipitation.
<h3>What is a Biome?</h3>
This is referred to an environment which is greatly influenced by abiotic factors such as soil, climate etc and varies all over the world.
Tropical rainforest as the name implies has a large and frequent amount of precipitation thereby making it wet with little seasonal variation in temperature. It is also characterized by large trees which form canopies in the region.
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