Multiple Choice QuestionsTwo opposite forces operate in the growth and development of every population. One of them is related to the ability to reproduce at a given rate. The force opposite to it is called
fecundity
environmental resistances
biotic control
mortality.
What is a keystone species
A species which makes up only a small proportion of the total biomass of a community, yet has a huge impact on the community's organization and survival.
A common species that has plenty of biomass, yet has a fairly low impact on the community's organization.
A rare species that has minimal impact on the biomass and on other species in the community.
A dominant a large proportion of the biomass and which affects many other species.
Assertion : Bursa fabricii lies on the ventral side of the cloaca in birds.
Reason : Bursa fabricii is related with flight adaptation.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
D.
If both assertion and reason are false
In birds, the bursa of Fabricius is the site of Hematopoisis, a specialized organ that is necessary for B cell development in birds. Bursa is a small, glandular, blind pouch of lymphatic tissue present on the dorsal side of the cloaca. It is lined with endoderm, and opens into the proctodaeum.
In a young bird, bursa fabricii forms lymphocytes, and probably it produces antibodies and protects against local infection, but it atrophies in the adult before sexual maturity. It is also called cloacal thymus, because like thymus, it secretes lymphocytes. Thus, it is not related with flight adaptation, rather it helps in immunity.
Assertion : The primitive atmosphere was reducing one i.e. without oxygen.
Reason : In the primitive atmosphere, oxygen was involved in forming ozone layer.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
Assertion : Jave Apeman, Peking man and Heidelberg man are the fossils of Homo erectus.
Reason : Homo erectus evolved from Homo habilis.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
Nicotiana sylvestris flowers only during long days and N.tabacum flowers only during short days. If raised in the laboratory under different photoperiods, they can be induced to flower at the same time and can be cross-fertilized to produce self-fertile offspring. What is the best reason for considering N.sylvestris and N.tabacum to be separate species
They cannot interbreed in nature.
They are reproductively distinct.
They are physiologically distinct.
They are morphologically distinct.
Wings of pigeon, mosquito and bat show
divergent evolution
atavism
convergent evolution
all of these
Assertion : The earliest fossil form in the phylogeny of horse is eohippus.
Reason : Eohippus lived during the early pliocene epoch.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
Assertion: The earliest organisms that appeared on the Earth were non-green and presumably anaerobes.
Reason: The first autotrophic organisms were the chemoautotrophs that never released oxygen.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false.
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