Give the scientific names of any two microorganisms inhabiting the human intestine.

In an association of two animal species, one is a termite which feeds on wood and the other is a protozoan Trichonympha present in the gut of the termite. What type of association they establish?

Lianas are vascular plants rooted in the ground and maintain erectness of their stem by making use of other trees for support. They do not maintain direct relation with those trees. Discuss the type of association the lianas have with the trees.

What is a tree line?

Define ‘zero population growth rate’. Draw a age pyramid for the same.