NEET Practice Questions (MCQs) with Answers & Solutions

The longer the chromosomes of an organism,the more genetic variability it gets from Crossing over. In Crossing over there is exchange of genetic material by the homologous chromosomes, resulting in recombinant chromosomes while sexual reproduction

Linkage refers to the tendency of genes located close to each other on the same chromosome to be inherited together. It generally reduces the formation of new recombinants because the linked genes do not assort independently. Therefore, the statement 'It helps in forming new recombinants' is incorrect.

The genetic balance theory for sex determination in Drosophila was proposed by C.B. Bridges. According to this theory, the sex of Drosophila is determined by the ratio of X chromosomes to sets of autosomes (X/A ratio).

Sex determination in Bonellia is governed by the presence or absence of bonellin, i.e., environmental factors. All larvae are genetically identical; if larva develops free in water it becomes adult female. The larvae that are exposed to bonellin in the skin of an adult female develop into males and are present in uterus of female. This makes option A wrong. Detachment of partly developed male from female body leads to its development into an intersex which makes option C wrong. Hence, option B is correct answer.

Progeny or individuals formed by the crossing of homozygous dominant and recessive parents is called F1 progeny and the generation is called F1 generation. Generation formed by the crossing of F1 progeny among themselves is called F2 generation.

So, the correct option is 'Crossing F1 individuals amongst themselves'

1. .

The probability of the fifth child being a daughter is 50%. Each child's gender is an independent event, meaning the outcome of one does not influence the others. The probability remains 50% for each child, regardless of previous outcomes.

In humans, the sex chromosomes are designated XX for females and XY for males. The XX - XY system is responsible for determining the sex of an individual. Females have two X chromosomes, while males have one X and one Y chromosome.

The number of linkage groups present in an individual corresponds to the number of chromosomes in its one genome (all the chromosomes if haploid or homologous pairs if diploid). ... Maize has 10 linkage groups, as it has 10 pairs of chromosomes haploid set is 10.

Crossing over during meiosis occurs between non-sister chromatids of homologous chromosomes. This process increases genetic diversity by exchanging segments of DNA, leading to new combinations of genes in the gametes.

Incomplete linkage refers to the situation where genes that are located close to each other on the same chromosome are not always inherited together. In Drosophila, incomplete linkage leads to the production of offspring with both parental and non-parental (recombinant) combinations. The percentage of non-parental combinations typically observed in incomplete linkage is 17%.