$A$ plant growing on another plant without drawing any nourishment is

What is the effect of a parasite on the host?

. . . . . . $A$ . . . . . . is a potent force in organic evolution. Identify the $A$.

If the '$+$' sign is used for a beneficial interaction,the '$-$' sign for a detrimental interaction,and the '$0$' sign for a neutral interaction,then which population interaction is represented by '$+$' and '$-$'?

Which of the following is an example of competitive interaction?

High density of elephants in a specific area is a result of which of the following?