Botany MCQs for NEET — Practice Questions with Answers

The gene that are carried on Y chromosome are called Holandric gene. This gene is responsible for "maleness". It is transferred from father to son.

Blood grouping in humans is controlled by three alleles: extit{I^A}, extit{I^B}, and extit{i}. The alleles extit{I^A} and extit{I^B} are dominant, while extit{i} is recessive. Therefore, the correct answer is that blood grouping is controlled by three alleles in which extit{I^A} and extit{I^B} are dominant.

Pleiotropism refers to the phenomenon where a single gene influences multiple phenotypic traits. This means that one gene can have multiple effects on an organism's phenotype, which is the definition of pleiotropism.

For children to have a 50% probability of having blood group AB, at least one parent must be heterozygous. If the father is heterozygous (IAi) and the mother is heterozygous (IBi), the possible genotypes of the children would be IAIB (AB), IAi (A), IBi (B), and ii (O). This results in a 25% chance for each blood group. However, to achieve a 50% probability for blood group AB, the correct interpretation is that either parent must be heterozygous.

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.