Organisms and Populations

Mutualism is found in

• hermit crab and sea anemone

• ox pecker and rhinoceros

• zoochlorellae and Hydra

• E.coli and man

Photochemical smog formed in congested metropolitan cities mainly consists of:

• ozone, peroxyacetyl nitrate and NO_x

• smoke, peroxyacetyl nitrate and SO₂

• hydrocarbons, SO₂ and CO₂

• hydrocarbons, ozone and SO_x

Assertion : Lateral line system is found in fishes and aquatic larval amphibians.

Reason : Lateral line system has receptors which are the clusters of sensory cells derived from ectoderm.

• If both assertion and reason are true and reason is the correct explanation of assertion.

• If both the assertion and reason are true but reason is not the correct explanation of assertion

• If assertion is true but reason is false

• If both the assertion and reason are false.

Which one of the following is a matching pair of certain organism(s) and the kind of association?

• Shark and sucker fish - commensalism

• Algae and fungi in lichens - mutualism

• Orchids growing on trees - parasitism

• Cuscuta (dodder) growing in other flowering plants - epiphytism.

Assertion : The age-sex structure of human population in countries like France and Germany gives a steep pyramid.

Reason : In countries like Sudan and India the population is increasing at a rapid rate.

• If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion

• If both Assertion and Reason are true but the Reason is not the correct explanation of the assertion

• If Assertion is true but Reason is false

• If both Assertion and Reason are false

Annual migration does not occur in the case of

• salmon

• siberian crane

• salamander

• salamander

Assertion : Inhabitants close to very busy airports are likely to experience health hazards.

Reason : Sound level of jet aeroplanes usually exceeds 160 dB.

• If both Assertion and Reason are true and the reason is the correct explanation of the assertion

• If both Assertion and Reason are true but the reason is not the correct explanation of the assertion

• If Assertion is true statement but Reason is false

• If both Assertion and Reason are false statements

On high mountains, difficulty in breathing is due to :

• decrease in partial pressure of O₂

• decrease in amount of O₂

• increase in CO₂ conc

• all of the above

Interbreeding population of animals is called :

• sub-species

• species

• community

• genus

Mr.X is eating curd/yoghurt. For this food intake in a food chain he should be considered as occupying

• first trophic leve

• second trophic level

• third trophic level

• fourth trophic level