Questions

The phrase ‘that he could not serve’ is grammatically correct. This is because other forms of verb doesn’t go with the blank and this form of verb is grammatically and contextually correct. Thus, the correct formation would be, ‘He was too conscientious in the discharge of his duties to serve that exploiter for long’.

It is the friction between the feet and the ground that helps us to walk. Without this friction we would slip and fall

The Surface tension pulls the surface of the drop equally at all points thus produces the spherical shape having the minimum surface area. This surface tension is the "skin" of a body of water that makes the molecules stick together.

Generic means related to a group of similar things rather than a particular one. It means it is not a specific thing like branded or trademarked. Hence it is a basic one.

Among the given options, Generic is most similar in meaning to Basic.