Below are given statements followed by some conclusions. You have to take the given statements to be true even if they seem to be at variance with the commonly known facts.
Statements:
1) Because of motor vehicles like cars, pollution has increased manifold.
2) Respiratory diseases are increasing due to pollution.
Conclusions:
I. If cars were not there pollution would be nil
II Doctors earn a lot due to pollution.
Decide which of the given conclusions logically follow(s) from the given statements.

What is the noise level of normal conversation?

If the radius (r) of a circle is increased by 'x' units, what is the number of units by which the circumference of the circle is increased?

If S means '$$+$$' L means '$$\times$$' U means '$$\div$$' and K means '$$-$$', then the value of
21 S 1 U 7 L 15 U 6 L 14 K 55 is

Find the missing (?) in the series
NA, QD, ?, WJ, ZM