Questions

A cell undergo meiosis, and it produces 4 haploid cells from a single diploid cell.

Hence, the given statement is true.

A rift valley is formed either due to upheaval of blocks on either sides of a fracture or due to subsidence of block between them.

Koala is a animal that exclusively eat only eucalyptus leaves and nothing else.

International Day for Disaster Reduction, held every 13 October, celebrates how people and communities around the world are reducing their exposure to disasters.

The year 2017 focus is : Reducing the number of affected people by disasters by 2030.

Black  surfaces are good emitters of heat ( They are also good absorbers of heat). If the black surface is rough too, the emitting will be better. So (b) is the correct answer. Shining surfaces reflect back radiation. So if the black surface is also shining the effectiveness of emitting heat is lessened.