Which of the following is a characteristic feature of viruses?

What happens when:
$(a)$ Borax is heated strongly,
$(b)$ Boric acid is added to water,
$(c)$ Aluminium is treated with dilute $NaOH$,
$(d)$ $BF_3$ is reacted with ammonia?

The correct reaction/reaction sequence that would produce a dicarboxylic acid as the major product is

An insulated cylindrical vessel is fitted with an insulated piston of negligible weight and negligible thickness at the midpoint of the vessel. The cylinder contains a gas at $0^{\circ} C$. When the gas is heated to $100^{\circ} C$,the piston moves through a length of $5 ~cm$. The total length of the cylindrical vessel in $cm$ is:

$A$ person is having problems with calcium and phosphorus metabolism in his body. Which one of the following glands may not be functioning properly?

Which of the following wiring diagrams could be used to experimentally determine $R$ using Ohm's law? Assume an ideal voltmeter and an ideal ammeter.