Name the following:

A hormone that stimulates growth by cell division.

Name the following:

A growth-retarding hormone in plants.

Define the following terms:

(a) Phytohormones

(b) Tropism

(c) Clinostat

(d) Apical dominance

(e) Parthenocarpy

(f) Abscission

(g) Heliotropism

List five plant growth hormones and mention one important role of each.