In laboratory experiments, two species of the protist Paramecium were grown alone and in the presence of the other species. The following graphs show growth of species 1 (left) and species 2 (right), both alone and when in mixed culture.
Interpretation of these graphs shows that
(a) Competitive exclusion occurred in these experiments.
(b) Both species are affected by interspecific competition but species 1 is affected less.
(c) Both species are affected by interspecific competition but species 2 is affected less.
(d) Both species are affected equally by interspecific competition.
