CBSE
Multiple Choice QuestionsThe equation = B represents, which of the following?
Natality
Growth rate
Mortality
All of these
Which one of the following is a population?
A spider and some trapped flies in its web
Earthworm that lives in a grassland along with other arthropods
All the plants in a forest
All the oak trees in a forest
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
Short Answer TypeWhat are mycorrhizae?
Multiple Choice QuestionsA biologist studied the population of rats in a barn. He found that the average natality was 250, average mortality 240, immigration 20 and emigration 30. The net increase in population is
10
15
05
Zero
When one organism is benefited without affecting the other, it is called
parasitism
commensalism
saprophytis
symbiosis
Photochemical smog formed in congested metropolitan cities mainly consists of:
ozone, peroxyacetyl nitrate and NOx
smoke, peroxyacetyl nitrate and SO2
hydrocarbons, SO2 and CO2
hydrocarbons, ozone and SOx
Zooplanktons are :
parasites
primary producers
primary consumers
primary decomposers
A sedentary sea anemone gets attached to the shell lining of hermit crab. The association is
ectoparasitism
symbiosis
commensalism
amensalism
Scirpophage incertulus is an example of
monophagus pest
diphagus pest
oligophagus pest
polyphagus pest
