Answer: Option B. -> Vernalization
:
B
Vernalisation refers specially to the promotion of flowering by a period of low temperature.It prevents precocious reproductive development late in the growing season, and enables the plant to have sufficient time to reach maturity.

Answer: Option A. -> Larkspur and buttercup
:
A
Production of different kinds of leaves by the same plant is called as heterophylly. Leaves of cotton, coriander, larkspur and buttercup show heterophylly.

Answer: Option C. -> Short day plants
:
C
It has been observed that some plants require a periodic exposure to light to induce flowering. Short day plants begin flowering when the days areshorterthan their critical day length.

Answer: Option B. -> Lag phase, log phase and steady phase 
:
B
In S - shaped or sigmoid growth, the population show an initial gradual increase in population size, followed by an exponential increase and then a gradual decline to near constant level.
Sigmoid growth curve is formed of five phases.
a) Lag phase -Period where individuals adapt to the new environment, so growth is slow.
b) Logarithmic or exponential phase (log phase) -Period of rapid rise in population due to availability of food and requirements in plenty and no competition.
c) Stationary phase (steady phase) - Finally, growth rate becomes stable because mortality and natality rates become equal. With limited nutrient availability, growth slows down.

Answer: Option B. -> Growth
:
B
Growth, reproduction, ability to sense environment, mount a suitable response to it, metabolism, ability to self replicate, self-organisation and interaction are some unique fundamental features of living organisms. Of these, growth is perhaps the most evident or conspicuous.

Answer: Option B. -> Dedifferentiation
:
B
Plants show another interesting phenomenon. Theliving differentiated cells, that by now have lost the capacity to divide can regain the capacity of division under certain conditions. This phenomenon is termed asdedifferentiation.For example, formation of meristems – interfascicular cambium and cork cambium from fully differentiated parenchyma cells.

Answer: Option C. -> ovum
:
C
The female gamete produced by the ovary is called ovum. Ovum is haploid in nature and it fuses withsperm to form a zygote.

Answer: Option D. -> Both the statements are incorrect
:
D
In the case of asexual reproduction, mitosis takes place. Mitosis produces daughter cells which are identical to the parent cell. If adiploid cell undergoes mitosis, it produces2 diploid cells.
In the case of sexual reproduction, reproductivecells undergo reduction division (meiosis) and produce 4 haploid cells from 1 diploid cell. These haploid cells are called sex cells or gametes.

Answer: Option D. -> Cow
:
D
Animals like cows, cats and dogs give birth to young individuals,hence they are calledviviparous animals whereas frogs, hens and silkworms lay eggs, and hence they are called oviparous.

Answer: Option B. -> less 
:
B
In case of external fertilisation, the number of eggs produced ismorethan the number of eggs produced in internal fertilisation.External fertilisation usually occurs in aquatic animals.Theseanimals lay hundreds of eggs and release millions of sperms.However,many of the eggsdo not get fertilised (fuse with sperm)todevelop into new individuals. This is because the eggs and spermget exposed to water currents and wind. Also, there are other animals (predators)which may feed on these eggs. Thus, production of a large number of eggs and spermis necessary to ensurefertilisation of at least a few of them.