In some trees and shrubs, competition among seedlings causes individuals to be spaced relatively evenly throughout the habitat. these plants exhibit a type of dispersion pattern.
a. ramet
b. random
c. clumped
d. regular

The correct answer is option D, that is regular or uniform.

Explanation:

The individuals in a population can be spaced in a distinct manner known as the dispersion patterns. The most common arrangement is the clumped dispersion in which these individuals are clustered together. In random dispersion, the individuals are aligned randomly, and in uniform or regular dispersion, the individuals are spaced evenly.  

The given case is an illustration of regular or uniform distribution. It is less common in comparison to clumped distribution. The pattern of uniform or regular distribution is witnessed in the populations of the species in which the distance between the adjacent individuals is enhanced. The requirement to enhance or increase the space between the individuals usually originates due to competition for a resource like nutrients or moisture.