Which one of the following is a characteristic feature of cropland ecosystem?
Least genetic diversity
The absence of weeds
Ecological succession
Ecological succession
Which of the following would appear as the pioneer organisms on bare rocks?
Liverworts
Mosses
Green algae
Green algae
Which of the following is required as inducer(s0 for the expression of lac operon?
galactose
lactose
lactose and galactose
lactose and galactose
When does the growth rate of a population following the logistic model equal zero? The logistic model is given as dN/dt = rN(1-N/K)
when N nears the carrying capacity of the habitat
when N/K equals zero
when death rate is greater than birth rate
when death rate is greater than birth rate
Which one of the following statements is not true?
Exine of pollen grains is made up of sporopollenin
Pollen grains of many species cause severe allergies
Stored pollen in liquid nitrogen can be used in the crop breeding programmes
Stored pollen in liquid nitrogen can be used in the crop breeding programmes
D.
Stored pollen in liquid nitrogen can be used in the crop breeding programmes
Tapetum is the inner layer of microsporangium which provides nourishment to developing pollen grains after meiotic division.
In bryophytes and pteridophytes, transport of male gametes requires
insects
birds
water
water
Analogous structures are a result of
convergent evolution
shared ancestry
stabilising selection
stabilising selection
Proximal end of the filament of stamen is attached to the
connective
placenta
thalamus
thalamus