Birds

(i) Heterokaryon. The fusion product of two different protoplasts is called heterokaryon.
(ii) Tumour. A cell or tissue which has the ability for unlimited growth is called tumour.
(iii) Somatic hybridization. The technique involving the fusion of isolated protoplasts from genetically different individuals is called somatic hybridization.

Significance of meiocytes. Meiocytes are gamete producing cells which undergo meiosis. They are diploid. As a result of meioses, they produce haploid gametes. During fertilization, fusion of haploid gametes restore diploid nature of zygote. It undergoes mitosis to form complete new young one.

The two male gametes produced by a pollen grain are used in the fertilisation of one ovule.
One male gamete fuses with the female gamete to form the zygote, i.e. syngamy.
The second male gametes fuses with the secondary nucleus, to form the triploid primary endosperm nucleus (PEN), i.e. triple fusion.
As double fertilisation (two fusions) occurs in the ovules of angiosperms, ten pollen grains are necessary to fertilise ten ovules.

Reasons
(i)There is a rapid decline in the death rate, maternal mortality rate and infant mortality rate(IMR)
(ii)There is an increase in the number of people in reproductive age
Steps taken by government
(i)Statutory raising of marriageable age of the females to 18 years and that of males to 21 years.
(ii)Providing incentives to couples with small families.

The menstrual cycle is controlled by rhythmic synthesis and release of ovarian hormones under feedback control from the hormones of anterior pituitary. These are discussed below:
(i) Pituitary hormones The gonadotroph cells, of anterior pituitary secrete FSH and LH in females. Their role in menstrual cycle are:
(a) Follicle Stimulating Hormone (FSH) It is secreted during the follicular phase of the cycle and is responsible for follicular development on induction of LH receptors on granulosa cells of the ovary.
(b) Luteinising Hormone (LH) Its primary function is to stimulate the formation of corpus luteum and secretion of estradiol and progesterone from ovary.
(ii) Ovarian hormones Ovary secretes the following hormones under the effect of FSH and LH.
(a) Oestrogen It influences proliferation of the uterine endometrium to prepare for implantation of the fertilised oocyte.
(b) Progesterone secreted from corpus luteum under LH influence, maintains endometrium for implantation It rising level inhibits LH.

(a) Sex education is important in schools
(i) to provide right information about myths and misconceptions.
(ii) to create awareness about reproduction.
(iii) to provide knowledge about growth of reproductive organs and sexually transmitted diseases. (STDs)
(iv) to guide the students about social evils such as sex abuse, sex-related crimes.
(b) Indicators about reproductively healthy society.
(i) Low infant mortality rate (IMR)
(ii) Low maternal mortality rate (MMR)
1. Increased number of couples with small families
2. Beller detection and cure of STDs.

(b) (i) Since the anthers of angiosperm flowers are bilobed with two thecae (sporangia) in each lobe, they are called dithecous.
(ii) The plants grown from the hybrid seeds show segregation of traits and do not maintain the hybrid characters; so hybrid seeds have to be produced every year.

(a) Grafting a branch from the tree of Ajay's house on a tree of Jagan's garden can be done.
(b) The part of the graft that forms the upper part is called scion and the part of the graft that becomes the supporting portion (the root and base), is called stock.
(i)  The scion is selected from a superior quality plant (juicy, larger mango fruits) while the stock belongs to the plant to be improved.
(ii) The scion and stock should be of same diameter and slant cuts are made on both the branches.
(iii)  The scion is kept on the stock, covered with grafting clay and polythene; it is tied well and arrangement of water supply/ moisturising is made.
(iv) After a few weeks, you will see buds and leaves appearing on scion.
(c)The mango tree will start producing flowers and fruits very early, may be in the next season itself. - Many branches can be grafted on the tree with poor quality mangoes.
(i) When grown from a seed it takes many years for the tree to produce fruits. - Sometimes the plant produced from the seed may not be of the same quality, as sexual reproduction results in variation.
(d) Values for friendship and generosity.

The presence of a chromogenic substrate gives blue coloured colonies, in absence of an insert/in non-transformants, presence of an insert (in the enzyme site), results into (insertional inactivation of the β-galactosidase) colonies which do not produce colour.
Antibiotic resistance method requires duplicate plating/cumbersome procedure.

As a biology student, i would suggest ex situ conservation approach for such animals. It involves placing the threatened animals and plants in special care units for their protection. It includes offsite collections (Botanical Gardens, Zoological Parks, etc) and gene banks (seedbank, tissue culture, etc).
Advantages of ex situ conservation are:
(i) Offsite collection can be used to restock depleted population, reintroduce species in the wild and restore degraded habitats.
(ii) It is useful in maintaining a large number of genotypes in small area, rapid multiplication of even endangered species, through tissue culture, etc.

(a) Submerged
(b) Rooted emergent
(c) Rooted with floating leaves 
(d) Free-floating
(e) Rotted-submerged.

Withdrawal syndrome.
These are the characteristic and unpleasant manifestations of the body,when regular dose of drugs/alcohol is abruptly discontinued.
Characteristics:
(i) Anxiety        
(ii) Excess sweating      
(iii) Shakiness  
(iv) Nausea.
In some cases withdrawal symptoms can be severe and even life-threatening.

(a) I  - Teritiary follicle
II  - Ampullary-isthmic junction
III  - Ampullary-isthmic junction
IV  - Endometrium of uterus.
(b) The signals originate from the fully developed foetus and the placenta.
Pituitary releases oxytocin,that stimulates stronger contractions of the uterine muscles.