Answer: A) Epiglottis Explanation: Epiglottis is that prevents food from entering the windpipe.  It is a cartilageous flap that flaps opens and closes when swallowing. When you swallow, the epiglottis flattens backward to cover the entrance to your larynx and prevent food from entering the lungs and windpipe. The epiglottis returns to its usual position after swallowing.

Answer: D) None of these Explanation:

Answer: A) Adenosine triphosphate Explanation: Adenosine triphosphate (ATP) is a nucleotide which is also called as nucleoside triphosphate is a small molecule used in cells as a coenzyme. It is often referred to as the "molecular unit of currency" of intracellular energy transfer. ATP transports chemical energy within cells for metabolism. Most of the cellular functions need energy in order to be carried out such as synthesis of proteins, synthesis of membranes, movement of the cell, cellular division, transport of various solutes etc. The ATP is the molecule that carries energy to the place where the energy is needed. When ATP breaks into ADP (adenosine diphosphate) and Pi (phosphate), the breakdown of the last covalent link of phosphate liberates energy that is used in reactions where it is needed.