Analogous organs: The organs which are similar in appearance and perform the same function but differ in their fundamental structure and orgin are called analogous organs.
Examples: 
1. Wings of birds and insects.
 2.Leaves of a plant and cladodes of Ruscus are also analogous organs.

(b) Leydig cells secrete testosterone, which is necessary for spermatogenesis.

(i) The DNA fragments may be used to construct recombinant DNA by joining them with cloning vectors .
(ii) The desired DNA fragments may be amplified, i.e. making multiple copies, by polymerase chain reaction (PCR).

The doctor must have used Pedigree analysis; which refers to the analysis of distribution and movement of traits in a series of generations of a family. Since the non-haemophilic parents give rise to a haemophilic child, the genotypes of them should be

The adenosine deaminase enzyme deficiency is caused by delection of a gene for ADA, an enzyme crucial for the immune system to function.

AIDS is a fluid transmitted disease and is considered as an STD because the probability of fluid transmission is maximum during sexual intercourse.

Yes.
Many animals other than human have self-consciousness. For example, dolphins are highly intelligent. They have a sense of self and they also recognise others among themselves. They can communicate with each other by whistles, tail slapping, and other body movements. Besides dolphins some other animals such as parrots, chimpanzees, orangutans, gorilla, etc. are also found to have self-consciousness.

Some Human Disorders

The technology used to run vehicles on dual mode like petrol or compressed natural gas is said to be hybrid vehicle technology. These vehicles runs on either petrol or CNG. As CNG is clean and green fuel so it is helpful to reduce environmental pollution and also to conserve petrol, fossil field.

Use of animals in biotechnological research causes greater suffering to the animals. But most people seem accept some animal suffering to serve the basic interest and welfare of mankind this attitude has been termed as interest sensitive speciesism. It is one of the most common ethical issue.

Honey is dense sweet liquid, containing sugars 20-40%, moisture 60-80%, minerals 0.22-0.3%, vitamins 0.2-0.5%, enzymes and pollen.

Over-crowded human settlements are generally with unhygienic conditions due to heaps of garbage,improper disposal of human and animal excreta, stagnant water sources, etc All these conditions increase the chances of spread of infectious diseases like amoebiasis (amoebic dysentary), cholera,typhoid, TB, etc.

Fragmentation.  It is a type of asexual reproduction. In some animals like Hydra and Planarian flatworms, there occurs the breaking up of the body into several parts due to one or the other reason. Then each part is called fragment which develops into a complete organism. In some worms and tunicates, it takes place spontaneously.

(i) Diphtheria
(ii) Whooping cough
(iii) Leprosy
(iv) Plague.

(i) Such practices of pest and pathogen control although help in increasing the agricultural yield and meet the increasing food demand of the ever increasing population but however they should be allowed and continued only after proper scrutiny and analysis so that the harm to the non target benificial organisms and the environment is minimum.
(ii) Biological control methods of pests and disease control should be preferred in place of the chemical control. The latter are non specific and costly and cause biological magnification while the biocontrol methods are the natural methods of pest and pathogen control and involve the use of natural
predators (e.g., bacteria, fungi) or their products because they are specified and do not harm the non target organisms. For example lady bird beetles brings about the biocontrol of aphid by feeding upon them and Trichoderma a fine living fungus exerts biocontrol on a number of plant pathogens due to its antifungal and antibacterial activity.
(iii) Ethical values with regard to the safety of environment have not been kept in mind.

(i) yes, the judgment is correct.
Couple X has blood groups O (man) and AB (woman).
Their genotypes and the progeny are as follow:

Thus Couple-X cannot have a child of O group blood, Couple Y has blood group A (man) and b (woman); since the child is O group (ii), both these parents must be heterozygous, i.e. man (I^A i) and woman (I^B i).The cross is shown below:

It is possible that child with O-group blood is produced by couple Y.
(ii) DNA-fingerprinting is another technique to solve the paternity cases.
(iii) The judge wanted to be very sure of the parents before pronouncing his judgment; he made his self conscience satisfied.