In this interaction, one is benefited and the other remains unaffected. 

 Raunkiaer gave the description of life-forms in plant communities.

A and E are not the features of hydrophytes. 

Fluctuations in natural population are affected by: birth and death rates, resources like food, water and space, natural calamities such as earthquake and volcanic eruptions, abiotic factors like temperature and rainfall, other organisms sharing habitat.

It is the ecological behaviour in which the animals inhabit the trees.

Kaziranga National Park is famous for one-horned rhinoceros.

Photochemical smog was reported in Los Angeles. This oxidising type of pollution is characterised by the presence of large concentration of ozone, oxides of nitrogen and various hydrocarbons.

Nitric oxide (NO) is formed by reaction between oxygen and nitrogen.

NO reacts with air forming NO₂.

NO₂ absorbs light and nitric oxide and nascent oxygen [O] are formed.

Nascent oxygen combines with molecular oxygen to form ozone.

Ozone reacts with unburnt hydrocarbons to give aldehydes and ketone.

Nitrogen oxides, oxygen and ketone give rise to PAN.

Excess of nitrates in drinking water causes methaemoglobin formation which results in blue baby syndrome or  methemoglobinemia.

The rate of total capture of energy or the rate of total production of organic material is gross primary productivity.

These are features of planktons. 

Hornbill and Indian aconite is a pair of endangered species.

This is the correct order.

 Genetic diversity is helpful in both adaptation and speciation.

Epiphytic plants hang in air, so they cannot absorb water from soil.

 Alpine meadows are seen where sediments from the weathering of rocks have produced soils, which are developed enough to support plants like grasses and sedges.