Question

What is a plant hormone? Give 4 different types of plant hormones and state their functions briefly.

Answer 1

what is a hormone?
it is a chemical, that communicates with the parts of the organism.

actually, there are 5 hormones and are called phytohormones

1. auxins - cell elongation
2.gibberllins - stem elongation
3. cytokinin - cell division
4. Abscissic acid - controls shedding of leaves 
5. ethylene - ripening of fruits

Answer 2

hey there!!!
plant hormones are the hormones secreted by plants for different purposes like growth etc
some plant hormones are
1)auxin:-this hormone is present on the shoot tip this helps in growth
2)gibberellins:-this hormone helps in growth like auxin
3)Cytokinins:-this hormone promotes cell division
4)Abscisic acid:-this hormone is different from auxin it stops growth of plant
hope this helps you