State one function of iris in human eye.

Write the name and formula of the second member of the carbon compounds having functional group-OH.

What happens when higher energy ultraviolet radiations act on the oxygen at the higher level of the atmosphere?

In a food chain, if 10,000 joules of energy is available to the producer, how much energy will be available to the secondary consumer to transfer it to the tertiary consumer?

Choose from the following:

₆C, ₈O, ₁₀Ne, ₁₁Na, ₁₄Si

(i) Elements that should be in the same period.

(ii) Elements that should be in the same group. State reason for your selection in each case