Answer:
Niche can be described as the role or position that a particular organism has in its ecosystem.
For example, honeybees which will gather nectar from flowers to make honey is an example of a niche. The particular role of honeybees in an ecosystem is to collect nectar in that ecosystem from different flowers and to produce honey. Other organisms living in the same environment will not perform the same function in the ecosystem.
Answer: Eating excessive quantities of such molecules could deregulate this process, increasing methylation and repressing the expression of genes that should normally be expressed.
Explanation:
DNA methylation is one of the epigenetic mechanisms involved in the regulation of gene expression, because it is a process by which methyl groups are added to DNA.
Methylation then modifies the function of DNA when it is found in the promoter gene, it is essential for normal development and is associated with a number of key processes, including genomic imprinting, inactivation of the X chromosome, repression of repeating elements, aging, and carcinogenesis. Usually, <u>it acts to suppress gene transcription.</u>
For example, folic acid is essential for the rapid cell division that occurs during early fetal development and it also plays an important role in methylation and thus in gene regulation. <u>The metabolism of these vitamins is aimed at achieving adequate levels of DNA methylation, necessary for the cellular processes</u>. Eating excessive quantities of such molecules could deregulate this process, <u>increasing methylation and repressing the expression of genes that should normally be expressed</u>.
A model of a globe is a physical model. The limits are that the solar system is too big to be seen all at once. From the Tennessee science textbook, "Many years ago, scientists thought that Earth was the center of the universe and the sky was a blanket that covered the planet. Later through the observation, it was discovered that the objects you see in the sky are the sun, the moon ,stars, and other planets. This new model explained the solar system differently.