The question asks about the conditions under which Mendel's Law of Independent Assortment applies. This law describes how different genes are inherited relative to each other. We need to recall the fundamental principle behind this law.
Correct Option: A) Genes are located on different chromosomes. This is the primary condition for Mendel's Law of Independent Assortment to hold true, as it allows for the independent segregation of alleles during gamete formation.
This question pertains to Mendelian genetics, specifically a monohybrid cross involving complete dominance. We need to determine the phenotype of the F1 generation when a pure tall plant is crossed with a pure dwarf plant.
B) All tall plants — As explained above, the cross between pure tall (TT) and pure dwarf (tt) plants results in all F1 offspring having the heterozygous genotype (Tt). Due to complete dominance, all these heterozygous plants will express the dominant trait, which is tallness.
The question asks about the primary location of sex-linked traits in humans. This requires knowledge of human genetics, specifically the difference between sex chromosomes and autosomes, and how traits are inherited based on their location on these chromosomes.
Correct Option: B) X chromosome — The X chromosome is significantly larger than the Y chromosome and contains many more genes. Therefore, the vast majority of sex-linked traits are carried on the X chromosome. These are known as X-linked traits, and they exhibit specific inheritance patterns, often affecting males more frequently than females.
The question asks to identify the type of genetic disorder Haemophilia is. To answer this, one needs to recall the inheritance pattern of Haemophilia, which is a well-known genetic condition.
C) X-linked recessive disorder — Haemophilia is indeed an X-linked recessive disorder. This means the defective gene is located on the X chromosome, and two copies of the defective gene (one on each X chromosome) are required for a female to be affected, while only one copy is sufficient for a male to be affected (since males have only one X chromosome). Females can be carriers without showing symptoms.
To understand why colour blindness is more common in males, we need to recall the principles of X-linked inheritance, specifically for recessive traits. Colour blindness is a classic example of such a genetic condition.
Correct Option: A) The gene is X-linked recessive and males have only one X chromosome. This statement accurately describes the genetic basis for the higher prevalence of colour blindness in males.
The question asks about the genetic cause of Down syndrome. This requires knowledge of common chromosomal abnormalities and their associated conditions.
Correct Option: D) Trisomy of chromosome 21. This is the definitive genetic cause of Down syndrome, where an individual has three copies of chromosome 21 instead of the usual two.