Is it easier to take out a nucleon (a) from carbon or from iron (b) from iron or from lead?

Apomixis in plant means development of a plant (A) from root cutting (B) without fusion of gametes (C) from fusion of gametes (D) from steam cutting

Angle of elevation of top of building is 30^(@) from place A and become 45^(@) from another place B that is 10 m from A towards the building as shown in the figure Height of building is :-