(i) 

(a)

(b) The pollen tube moves through the style and reaches the ovule. It carries male gerrn cells to the ovule for fertilisation.
(c) (i) Ovules develops into seed.
(ii) Ovary develops into fruit.

Evidences are:
(a) Homologous organs: Organs which have same structure but different function. E.g., wings of a bat, hands of man and limbs of monkey.
(b) Analogous organ. Organs which perform similar function but are structurally different are called analogous organ. E.g., wings of bat, insects, birds.
(c) Vestigial organs: These organs are those which appear in an organism but are functionless e.g., vermiform appendix, nictitating membrane in eye is present in human beings but has no function.
(d) Embryological evidence: The study of embryos of vertebrates shows that all of them have same origin as their structure at initial stage is same. Embryo of frog, fish, man looks alike.
(e) Fossils as evidence: Archaeopteryx fossils shows a link between bird and reptiles as this fossil has some feature of bird and some of reptile.

(i) Traits: A characteristic feature is called trait.
(ii) Inherited and acquired trait: Inherited traits are the characteristics transmitted from parents to their offspring. Acquired traits are characteristics which are developed during the lifetime of an individual. Acquired traits are not passed on to the next generation. For example, if we breed a group of mice, all their progeny will have tails. Now, if the tails of these mice are removed by surgery and allowed to breed, the next generation mice will also have tails. If these tails are also removed and allowed to breed, the progeny of mice will again have tails. Removal of tail by surgery is an acquired trait and do not change the genes of germ cells and hence, are not passed on to the next generation.
(iii) Speciation and factors: It is the process of evolution of a new species from pre-existing species. Occurring due to accumulation of variations. The processes like genetic drift/geographical barriers like mountains, rivers etc., lead to incapability to reproduce amongst themselves in the population.

The egg gets fertilised in the oviduct. The fertilised egg, the zygote gets implanted in the lining of the uterus and starts dividing. The uterus prepares itself every month to receive and nurture the growing embryo. The lining thickness and is richly supplies with blood to nourish the growing embryo.
The embryo gets nutrition from the mother's blood with the help of a special tissue called placenta. The development of the child inside the mother's body takes approximately nine months. On completion of 9 months, the child is born as a result of rhythmic contractions of the muscles in the uterus.
If the egg is not fertilised, the thick and nourishing lining of the uterus breaks and comes out through vagina as blood and mucous.

In sexual reproduction, two individuals having different variations combine their DNA to give rise to a new individual. Therefore, sexual reproduction allows more variations, whereas in asexual reproduction, very less chance of variations can only occur when the copying of DNA is not accurate. However, if there are more variations, then the resultant DNA will not be able to survive inside the inherited cellular apparatus. Thus, the resultant DNA will be able to survive making the variations viable. Variants help the species to survive in all the conditions. Environmental conditions such as heat, light, pests, and food availability can change suddenly at only one place. At that time, only those variants resistant to these conditions would be able to survive. This will slowly lead to the evolution of a better adapted species. Thus, variation helps in the evolution of sexually reproducing organisms.

Phylogeny is the evolutionary history of an organism. Molecular phylogeny traces the evolutionary relationships by comparing the differences in the DNA of different organisms.

Copying of DNA occurs during cell division.

(a) Round yellow
(b) Round yellow, Round green, Wrinkled yellow, Wrinkled green.
(c) Wrinkled green
(d) Round yellow.

AIDS stands for Acquired Immune Deficiency Syndrome.
Four methods of prevention or control of AIDS are as follows:
(i)Use condom during sex
(ii)Avoid sharing of needles.
(iii)Test blood for AIDS before transfusion.
(iv)Avoid sexual contact with unknown person.

(a) No, she should not take the medicine.
(b) Of course she should visit a doctor to get information.
(c) She is having 50% chances of having a male child as 50% sperms carry Y chromosome and 50% X chromosome.

The ratio of chromosome number between and egg and its zygote is 1:2. Sperm and eggs are genetically different in terms of the nature of the 23rd chromosome. The 23rd chromosome is an Y chromosome in sperm, while it is an X chromosome in egg.

(a) (i) Oral contraceptive pills may disturb the hormonal balance of the body. 
(ii) Copper-T cannot prevent sexually transmitted diseases.
(b) The use of condom is kept under barrier method of contraceptives. The condoms are better contraceptive method as compared to others due to the following reasons.
(i) It helps to prevent STDs.
(ii) It cannot disturb the hormonal balance of the body and normal menstrual cycle in females.

(i) Hyphae is the non-reproductive parts of bread mould whereas, sporangia present on hyphae is the reproductive part.
(ii) (a) Vegetative propagation helps in growing seedless plants.
(b) It helps in the preservation of the characters of the parent plant.

(i) When tall pea plant (TT) is crossed with dwarf pea plant tt, every progeny is inherited with tall and dwarf gene together. Tall is dominant character, so plant becomes tall.
(ii) The genotype of F₁ progeny is Tt.
The selfing between these plants is done in the follow way to obtain F₂ progeny

	T	t
T	TT Tall (homozygous)	Tt Tall (Heterozygous)
t	Tt Tall (Heterozygous)	tt Dwarf (Homozygous)

Here, recessive and dominant gene get segregated and we obtain one tall (homozygous), one dwarf (homozygous) and two tall (heterozygous) plants.
(iii) This cross shows the law of segregation of character. lt means character like tall and dwarf plant height do not mix while crossing them.

Genotype: The complete set of genes in an organism's genome is called genotype.
Phenotype: The observable characters in an organism make the phenotype. Phenotype is a result of genotype's interaction with the environment. Due to this reason, many phenotypes are not inheritable.

Justification: Women produce only one type of ovum (carrying X chromosome) and males produce two types of sperms (carrying either X or Y chromosome) in equal proportions. So the sex of a child is a matter of chance depending upon the type of sperm fertilizing the ovum.

According to Darwin, natural selection is the process which brings about evolution of new species of plants and animals. It consists of the following processes:
(i) He noted that the size of population tends to remain constant despite the fact that more offsprings are produced than needed.
(ii) Variations provide adaptations.
(iii) The best adopted survive in the changing environment (survival of the fittest).
(iv) Nature selects the best organisms with better adaptations and after many generations new species are formed (natural selection).  

(b) Both A and R are true but R is not the correct explanation of A.
Dominant alleles mask the expression of recessive counter part.

(d): When pureline pea plants having round yellow seeds are crossed with that of wrinkled green seeds then plant obtained in Flare all with round yellow seeds as round yellow seeds are dominant to wrinkled green seeds.

(a): Mendel chose pea plants for studying inheritance because of number of reasons. Pea plants are self pollinating which enables them to produce next  generation of plants easily, also pure lines could be easily obtained. Due to short life cycle, many generations of pea plants can be produced in a comparatively short span of time. Also pea plant shows a number of clear cut visible contrasting traits like tall and dwarf height, round and wrinkled seeds, etc.

(c) : Insects help in cross-pollination. When an insect sits on the flower of a plant for sucking nectar then the pollen grains from anther of the flower stick to its body and when this insect sits on another flower of similar plant, pollen grains sticking to its body are transferred to the stigma of another flower. In this way, the insect transfers the pollen grains from the anther of flower in one plant to the stigma of flower in another plant and causes cross-pollination. The blowing wind also carries pollen grains from one flower to another flower and helps in cross pollination.

(d): All the sepals taken together are called calyx.

(b). If both assertion and reason are true but reason is not a correct explanation of assertion.