Pure tall plants are crossed with pure dwarf plants. In the F₁ generation, all plants were tall. These tall plants of F₁ generation were selfed and the ratio of tall to dwarf plants obtained was 3 : 1. This is called

• dominance

• inheritance

• codominance

• heredity

Chromosome complement with 2n - 1 is called

• monosomy

• nullisomy

• trisomy

• tetrasomy

The trisomy for 21st chromosome is called

• Down's syndrome

• Turner's syndrome

• Sickle cell anaemia

• Klinfelter's syndrome

Chromosome complement with 2n - 1 is called

• monosomy

• nullisomy

• trisomy

• tetrasomy

L- shaped chromosomes are also called

• acrocentric

• telocentric

• sub- metacentric

• None of these

If root of a flowering plant has 24 chromosomes, then its gamete has how many chromosomes?

• 24

• 12

• 4

• 8

Balbiani rings are the structural features of

• allosomes

• polytene chromosomes

• autosomes

• Lampbrush chromosomes

X- linked recessive gene is

• always expressed in male

• always expressed in femlae

• lethal

• sub- lethal

Which of the following is a test cross?

• Tt $\times$tt

• TT $\times$tt

• Tt $\times$Tt

• tt $\times$tt

1 : 2 : 1 phenotypic and genotypic ratio is found in

• complementary genes

• blending inheritance

• multiple alleles

• pseudo alleles