Read the excerpt from “Exploring the Secrets of Marsh Happiness” by NOAA. According to the study, “happy,” or persistent, marshes all shared common traits. What healthy marshes shared most of all was vegetation distributed on the higher end across low-to-high landscape elevations. The single most important measurement in assessing a “happy” tidal marsh is whether a sizeable proportion of its vegetation is at a high elevation in relation to current water levels. Another feature of “happy” marshes is a low percentage of unvegetated versus vegetated area in the marsh landscape.

What is the meaning of “happy” as used in the excerpt?

A.
indifferent
B.
enduring
C.
fortunate
D.
content