a) This is the shoot apex meristem of a dicotyledonous plant.

The shoot apical meristem is present at the tip of the plant stem, has two functions:

a) it is the point of source of new cells needed for growth stem

b) small cellular outgrowths occurs here called leaf primordia that later develop into leaves

The different parts labelled 1,2, 3 are:

1: Leaf primordium

2: Axillary bud: During the formation of leaves and elongation of stem, some cells which are left behind make the axillary bud: forms a branch or a flower.

3: Shoot apical meristem

b) If part 1 is removed from the plant, then the apical bud is inhibited while there is growth of lateral buds.