(iii) Name the type of age pyramid in which the number
of pre-reproductive and reproductive individuals are
almost same.
- (i) What is net primary productivity of an ecosystem?
(ii) Why do temperate regions show a lower value of primary
productivity as compared to tropical regions? Give two
reasons.
SECTION - D
- The police department obtained a few strands of hair
from the gripped hand of a murdered man. There were
two persons suspected in this criminal case, the murdered
man’s son and his servant. How will the forensic
department nab the real culprit as the son is repeatedly
accusing the servant? explain the technique.
SECTION - E - Study the graph given below and answer the questions
that follow :
(i) Name the hormones ‘X’ and ‘y’.
(ii) Identify the ovarian phases during a menstrual cycle’s:
(a) 5 th day to 12th day
(b) 14 th day
(c) 16 th day to 25th day
(iii) explain the ovarian events (a), (b) and (c) under the
influence of hormones ‘X’ and ‘y’.
OR
(i) Give a diagrammatic representation of spermatogenesis
in humans.
(ii) at which stage of life, does gametogenesis begin in
human male and female?
(iii) Name the organs where gametogenesis gets completed
in human male and female respectively.
- Define the term ‘biofertilizer’. How does each of the
following serve as a biofertilizer?
(i) Azospirillum
(ii) endomycorrhiza
(iii) Rhizobium
(iv) Azolla
OR
(i) Mention any 3 useful applications of Lactobacillus.
(ii) Name the microbes from which cyclosporin a (an
immunosuppressive drug) and statins (blood cholesterol
lowering agents) are obtained.- (i) explain bOD.
(ii) at a particular segment of a river near a sugar factory,
the bOD is much higher than the normal level. What is it
indicative of? What will happen to the living organisms
in this part of the river?
(iii) under what conditions will the bOD be lowered in the
river? How will it affect the aquatic life?
OR
(i) What is meant by ozone shield? Name two gases that
can cause damage to this shield. Give one harmful effect
of this damage each on plants and animals.
(ii) Why is global warming a warning to mankind?
SOLUTIONS - (c) Cucumber
- restriction enzymes act within palindromic sequences.
In the given DNa strand, point b shows a palindromic
sequence. Thus, it can be a probable site of restriction
enzyme action. - Virus infected cells produce antiviral proteins called
interferons, which on reaching the nearby infected cells,
make them resistant to viral infection. Thus, they provide
innate immunity. - (i) PCr (ii) eLISa
- Primary succession takes a very long time for completion
i.e., from 1000 years to several thousand years. - The milk produced by mother during the initial few days
of lactation is called colostrum, which contains several
antibodies (primarily Iga) absolutely essential to develop
passive immunity in the new-born babies.
Secretion and storage of milk generally begins after the
birth of young one, usually within 24 hours, under the
influence of hormone prolactin (PrL), secreted by anterior
lobe of the pituitary gland.
However, the ejection of milk is stimulated by the
hormone oxytocin (OT), released from the posterior lobe
of the pituitary gland. Secretion of PrL and OT depends on
suckling stimuli produced by nursing infant on nipples.