Plant growth caused by external stimulus is
a. tropism
b. homeostasis
c. gibberllin
d. hormone

The correct answer for the blank is-

A. tropism.

Tropism is a biological process that indicates growth of a plant in a particular direction in response to any external stimuli (any change in the environment that induces a specific response in a biological system).

For example - Phototropism in plants is a type of tropism process in which plants tend to grow towards the direction of sunlight.

Thus, option A) is the right answer.

it's     c       this is a cell (b) with a nucleus (c) containing dna (a). the dna is organized into chromosomes (d). a section of the chromosome that codes for a trait is called a gene (e).

supercell thunderstorms are perhaps the most violent of all thunderstorm types, and are capable of producing damaging winds, large hail, and weak-to-violent tornadoes