D is the best answer. Hope this helped :)
Explanation:
Percentage w/v means that weight of solute present in 100 ml of a solution. Hence, 15% w/v means that 15 gram of solute per 100 ml of solution.
Hence, for 2 L (or 2000 mL) preparation the amount of mass will be calculated as follows.

= 300 g
Thus, we can conclude that weight of Tris-HCL required is 300 g.
Answer:
The correct answer is - option D. nonsense and frameshift.
Explanation:
If there is a change in the sequence of DNA resulting in premature stop codon mRNA during transcription is known as a nonsense mutation and result in a non-functional protein.
a frame-shift mutation takes place when at least two nucleotides are altered and there are less chances to be changed by two others coding for the same nucleotide. It leads to a non-functional protein.
A cell wall is a structural layer that surrounds some types of cells, situated outside the cell membrane. It can be tough, flexible, and sometimes rigid. It provides cells with both structural support and protection, and also acts as a filtering mechanism. Cell walls are present in plants, fungi and prokaryotic cells, where a major function is to act as pressure vessels, preventing over-expansion when water enters the cells. Cell walls are absent from mycoplasmas.
The most commonly used algorithm is RSA