Questions

The purines are bases in the DNA. The two purines in DNA are Adenine and Guanine. These two purines forms hydrogen bonds with their complimentary pyrimidines such as Thymine and Cytosine to keep the two rails of the DNA molecule together.

A protein is being assembled when RNA is being translated. This process goes as, by the process of transcription first DNA is is converted to mRNA. And then by the process of translation this mRNA is converted to proteins.

=> DNA ----> mRNA ----> Proteins.

Any factor limiting the size of a population whose effect is not dependent on the number of individuals in the population, then such factor is called Density Independent Factor. It is things that the organisms have no control over.

Here in the given options, food shortage and disease are factors that are dependent on the number of population but Floods have no dependency.

Some examples of density independent factors are :: Earth quake, fires, volcanic eruptions, floods, and  all natural calamities.

Pascal's law is a principle in fluid mechanics that states that a pressure change occurring anywhere in a confined incompressible fluid is transmitted throughout the fluid such that the same change occurs everywhere.

This principle is stated mathematically as: P= P + rgh

The purpose of hydrogenating unsaturated fats is to make them more solid at room temperature as it is easy store the product.

Gene is a hereditary unit consisting of a sequence of DNA that occupies a specific location on a chromosome and determines a particular characteristic in an organism.

In short it is a piece or segment of chromosome.

Genes undergo mutation when their DNA sequence changes.