Diagrams X and Y above are illustrations of transverse sections of a part of plants, Study them and answer this question.

The part labelled Il is the?

The organelles in cells which are also referred to as suicidal bags are the 

The process that brings about the shrinking of a spirogyra cell when placed in a strong solution is ?

The region of a plant stem in which cells divide to increase its diameter is

The total number of caudal vertebrae in animals X and Y is 4 and 27 respectively. The animals are likely to be.