Growth that results in an increase in the girth of a plant is referred to as:

A) horizontal growth.
B) longitudinal growth.
C) primary growth.
D) radial growth.
E) secondary growth.

Secondary Growth

An increase in the girth of a plant due to the activity of the vascular cambium and cork cambium; secondary growth results in the production of secondary tissues (i.e., wood and bark).

Horizontal Growth

Expansion or growth of an entity (such as a company or plant) outward rather than upward, which can involve increasing product lines or locations.

Radial Growth

The pattern of growth that expands outward in all directions, commonly observed in fungi, certain plants, and some animals like jellyfish.