The density of a population in a habitat per unit area is measured in different units. Write the unit of measurement against the following:

a. Bacteria _______________

b. Banyan _______________

c. Deer _______________

d. Fish _______________

Categorise the following plants into hydrophytes, halophytes, mesophytes and xerophytes. Give reasons for your answers.

a. Salvinia

b. Opuntia

c. Rhizophora

d. Mangifera

In a pond, we see plants which are free-floating; rooted–submerged; rooted emergent; rooted with floating leaves. Write the type of plants against each of them.

a. Label the three tiers 1, 2, 3 given in the above age pyramid.

b. What type of population growth is represented by the above age pyramid?

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?