Questions

A 40% solution of Formaldehyde known as Formalin is used in the preservation of biological specimens because of its hardening action on proteins. 

Normality is a way of expressing concentration of a solution and can be calculated by the formula-

Normality (N) = No. of gram equivalent of solute/ volume of solution (in litre)

Gram equivalent weight of H2 SO4 = Molecular weight/ No. of Hydrogen atom = 98/2 = 49 gm

No. of gram equivalent in 49 gm of H2 SO4 = 1

So, Normality in 1 litre of solution = 1/1 = 1 N

Veins are blood vessels that carry blood toward the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenated blood to the heart. In contrast to veins, arteries carry blood away from the heart.

Veins are less muscular than arteries and are often closer to the skin. There are valves in most veins to prevent backflow.

Town planning, Drainage system and Use of Bronze are the features of Indus Valley Civilization. Use of Iron was not the feature of this.

A metaphor is a figure of speech that is used to make a comparison between two things that aren't alike but do have something in common.

In all the given options we have Metaphors.