What did Gause demonstrate regarding ecology and competition?

In biological interactions,what does the interaction type $(+, 0)$ represent?

Give one example for each of the following types:
$(a)$ Migratory animal
$(b)$ Camouflaged animal
$(c)$ Predator animal
$(d)$ Biological control agent
$(e)$ Phytophagous animal
$(f)$ Chemical defense agent

Given below are two statements $:$
Statement-$I$ : Species facing competition might evolve mechanisms that promote co-existence rather than exclusion.
Statement-$II$ : In endoparasites,morphological and anatomical features are greatly simplified while emphasising their reproductive potential.
In the light of the above statements,choose the correct answer from the options given below.

Which of the following statements is incorrect?

What is commensalism?