A J-curve of population size identifies a. a decreasing population
b. linear growth
c. a constant population size
d. a population at carrying capacity
e. exponential growth

d.a population at carrying capacity

i hope this helps u i m not sure about the answer though

a "theory" a suggestion that is not 100 % accurate, or a figure. some people say its a theory because they of all the passed theory's about one subject. it depends sometimes theory might be accurate and sometimes they are.