Which one of the following is one of the characteristics of a biological community?

A country with a high rate of population growth took measures to reduce it. The figure below shows age-sex pyramids of populations A and B twenty years apart. Select the correct interpretation about them : –

Reduction in vascular tissue, mechanical tissue and cuticle is characteristic of :

Consider the following four statements (1-4) about certain desert animals such as kangaroo-rat.
(i) They have dark colour and high rate of reproduction and excrete solid urine
(ii) They do not drink water, breathe at a slow rate to conserve water and have their body covered with thick hairs
(iii) They feed on dry seeds and do not required drinking water
(iv) They excrete very concentrated urine and do not use water to regulate body temperature
Out of these four, which two are correct-