(a) It is a dominant trait.
(b) It is autosomal.
(c) Genotypes of parents in generation I:
Female aa; male Aa.
Genotype of third child in generation II: Aa.
Genotype of first grandchild in generation III: Aa

Mendel performed his experiments on pea plants,i.e pisum sativum.After eight years of tedious experiments with pea plants, he proposed three fundamental principles of inheritance.These principles eventually assisted clinicians in human disease research,e.g after a few years of the discovery of Mendel's work,Archibald Garrod applied Mendel's principles to his study of alkaptonuria.Today, Mendalwhether we talk about pea plants or humans,genetic traits that follow the rules of inheritanceMendel proposed are called Mendelian Principles.

An example for this condition is sickle-anaemia. The person with homozygous condition (Hb^s  Hb^s ) for sickle-cell anaemia does not survive beyond the age of 20 years.
The individual with normal gene (HbHb) does not have sickle-cell anaemia but they are sensitive towards malaria.
The person with heterozygous condition (HbHb^s) for sickle-cell anaemia does not develop both sickle-cell anaemia and malaria.
Due to abnormal haemoglobin, the malarial parasite will not harm the person.
Hence, in this case, the heterozygous condition has more survival chances, an advantage with respect to the homozygous individuals.

male sex is determined by Y-chromosome which does not bear the gene for haemophilia.In the given case, when a normal male marries a carrier female the resultant offsprings will be follows- this marriage results in the four types of offsprings in equal ratio i.e .,
Normal Girl with XX genotype
Normal boy with XY genotype
carrier Girl with XX^h genotype
The defect of haemophilia does not appear in the girl carrier because the second X chromosome possesses therefore female child can be a carrier but does not develop diseases.The  male child on the other hand can develop the disese.

The number of linkage group in an organism corresponds to its haploid number of chromosomes.Therefore the number of linkage groups in the given organism is 8.

In case of cockroaches the males have old sex chromosomes (AA + X)whereas the female have two homomorphic sex chromosomes(AA + XX) The male cockroach is heterogametic and produces two type of gemetes A+ X , A + O.The progeny is obtained in the ration of 50 male : 50 females.The genotype of offsprings 50% AA+XX and 50% AA+XO

The phenomenon that strongly favours the linear arrangements of genes on the chromosomes, is linkage.linkage is the tendency for allells of different genes to pass together from the generation to the next.The genes located on different chromosomes cannot show any linkage.

If man is homozygous-I^AI^A and woman is also homozygous -I^BI^B then the offsprings will be -I^AI^B

If the man is hetrozygous-I^AIⁱ and the woman - I^BIⁱ then the offsprings will be

Thus the genotypes of parents are
Man=I^AIⁱ       woman=I^BIⁱ
genotypes of offsprings are-I^AI^B , I^AIⁱ ,I^BIⁱ and IⁱIⁱ

(a) All the flies of F₁ generation were red eyed.
(b) It was a set a test cross and the result was 1 red eyed female : 1 white eyed female : 1 red eyed male : 1 white eyed male
(c) All the males were white eyed and all the females were red eyed.

The phenomenon is point mutation that involves substitution of a single nitrogenous base in DNA.