Answer: A) Non-elastic effects Explanation: Rolling friction or rolling drag is the force resisting the motion when a body rolls on a surface. It is mainly caused by non-elastic effects, that is, not all the energy needed for deformation of the wheel, roadbed, etc... is recovered when the pressure is removed. Another cause of rolling resistance lies in the slippage between the wheel and the surface, which dissipates energy.

Answer: C) unicellular Explanation: An organism is a living thing, and there are two broad categories of organisms: those made up of only a single cell, and those made up of multiple cells. Single-celled organisms means which contains only one cell are called unicellular organisms. 'Uni-' means 'one,' so the name 'unicellular' literally means 'one cell.'   Examples of Unicellular or Single celled organisms ::   Prokaryotic organisms like Bacteria,... Some algae like green algae, euglena,...

Answer: C) DNA replication Explanation: S-phase (synthesis phase) is the part of the cell cycle in which DNA is replicated, occurring between G1 phase and G2 phase. Precise and accurate DNA replication is necessary to prevent genetic abnormalities which often lead to cell death or disease.