Transpiration ratio is the ratio of moles of H2O transpired/moles of CO2 fixed. This ratio is measure of
It is possible to determine whether an element is essential by observing growth of plants
What is genetic diversity ?
Evolution of different species in a given area starting from a point and spreading to other geographical areas is known as :
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Solution
Process of evolution of different species in a given area starting from a point and radiating to other area of geographical areas is called adaptive radiations. Example : Darwin’s finches, Australian marsupials.
Plants give off oxygen because
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Solution
Water is split at photosystem–II to donate electrons to the reaction centre. The resulting protons are moved across the membrane to establish the proton motive force and oxygen is given off as a by-product.
Thermal pollution of water bodies is due to
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Solution
Due to nuclear and other conventional sources,temperature of water bodies and atmosphere increases,which has adverse effect on different organisms.
Which one of the following describes the correct sequence of stages during embryogenesis?
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Solution
The zygote initially undergoes cleavage until the blastula stage is reached. Gastrulation is a drammatic rearrangement of the cells of the blastula.
Sharks and dogfishes differ from skates and rays by
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Solution
Sharks and dogfishes have cylindrical body while skates and rays have flattened body with wing like pectoral fins which are not distinct from body.
People who have migrated from the planes to an area adjoining Rohatang Pass about six months back :
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Solution
People going to hilly areas will have polycythemia (more number of RBC in blood) after six months and their Hb has a lower binding affinity to O2.
Which of the following events does not occur during the closing of stomata?
Which of the following has been recently used for increasing productivity of super milk cows?
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Solution
In superovulation, a high milk yielding cow is induced to shed 4–6 eggs (instead of one) every 6–8 weeks(instead of 20–21 days). The superovulated donor is artificially inseminated with semen from a quality bull.The embryos developing from the eggs so fertilised are flushed out. These good quality embryosare now transferred to surrogate mother for delivery.
Refer the given flow chart of the mode of action of AIDS virus and answer the following questions. Identify the labelled sequences A, B, C and D.
Which of the following statements is/are not true ?
(1)In Urochordata, notochord is present only in larval tail.
(2)In cephalochordata, notochord extends from head to tail region.
(3)Branchiostoma belongs to Hemichordata.
(4)Only one class of living members, class cyclostomata represents the super class agnatha
Metameric segmentation is the characteristic of
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Solution
Metameric segmentation means body is divided externally as well as internally. This characteristic is present in annelida (e.g.earthworm) and arthropoda (e.g.cockroach). Their body is divided externally and internally as well
Which of the following cations is required for the conversion of prothrombin into active thrombin by thromboplastin?
Fenestra ovalis is the opening of –
Which one of the following is a naturally occurring growth inhibitor ?
Fruit-eating bats tend to feed extremely rapidly on fruits and have relatively inefficient digestion(some times defecating seeds as early as an hour after feeding on them).Why are they good seed dispersal agents ?
Which one of the following pathogens causes canker disease ?
Human cells in culture show a cell cycle to be completed in approximately