While explaining interspecific interaction of population, $(+)$ sign is assigned for beneficial interaction,$(-)$ sign is assigned for detrimental interaction and $(0)$ for neutral interaction. Which of the following interactions can be assigned $(+)$ for one species and $(-)$ for another species involved in the interaction?

Animals eating plants are categorised separately as ...$A$..., they are in a broad ecological context, not very different from ...$B$...

Choose the correct option $A$ and $B$

What is a keystone species

Define ectoparasite and endoparasite and give suitable examples.

An interesting modification of flower shape for insect pollination occurs in some orchids in which a male insect mistakes the pattern on the orchid flower for the female of his species and tries to copulate with it, thereby pollinating the flower. This phenomenon is called

Carnivorous animals - lions and leopards, occupy the same niche but lions predate mostly larger animals and leopards take smaller ones. This mechanism of competition is referred to as