Maximum growth rate occurs in 

Zone of atmosphere near the earth surface is 

A terrestrial animal must be able to

What is a keystone species?

The term ecology was coined by

Very small-sized animals are rarely found in polar regions.  Give two reasons.

How does the human body maintain a constant temperature both in summers and winners? Explain.

How do organisms which cannot migrate tend to overcome adverse environmental conditions?  Explain taking one example each from vertebrates and angiosperms, respectively.

Write a short note on the adaptations of plant to water scarcity.

List three symptoms of high altitude sickness and state three adaptations to overcome it.

How do organisms like fungi, zooplanktons and bears overcome the temporary, short-lived climatic stressful conditions?  Explain.

Why is predation required in a community of different organism?

Describe any three reproductive strategies that organisms have evolved in relation to a particular set of selective pressures.

Competition does not always occur between closely related species for the same resources.  Substantiate the statement with examples.

(a) Explain with the help of a graph, the population growth curve when resources are
(i) limiting and
(ii) not limiting.
(b) 'Nature has a carrying capacity for a species'.  Explain.

List the different ways by which organisms cope or manage with abiotic stresses in nature.  Explain any three ways listed.

Water is the most important factor influencing the life of organisms.  Life on earth originated in water and cannot be sustained without water.  Organisms living in water bodies (ocean, lake, river, etc.) also face water-related problems.
(a) How are aquatic animals affected by the quality of water? Explain.
(b) Mention any four adaptations the desert plants have, to live there successfully.
(c) Represent the value learnt.

No species can exist alone in a habitat.  Any species has a minimal requirement of at least one more species, on which it can feed.  Interspecific interactions arise from the interaction of populations of two different species.
(a) What term is given to the interaction, where one species is benefitted and the other is neutral?
(b) Give four examples of the above kind of interaction.
(c) How do you call the interaction where one species is neutral and the other is harmed? Give an example of such an interaction.
(d) What value do you learn from this?