F₂ generation in a Mendelian cross showed that both genotypic and phenotypic ratios are same as 1:2:1. It represents a case of 

(1) codominance

(2) dihybrid cross

(3) monohybrid cross with complete dominance

(4) monohybird cross the incomplete dominance

Which one of the following conditions correctly describes the manner of determining the sex in the given example?

(1) XO type of sex chromosomes determine male sex in grasshopper

(2) XO condition in humans as found in Turner syndromee, determines female sex

(3) Homozygous sex chromosomes (XX) produce male in  Drosophila

(4) Homozygous sex chromosomes (ZZ) determine female sex in birds

Mutations can be induced with 

(1) IAA

(2) ethylene

(3) gama radiations

(4) infra red radiations

Which one of the following cannot be explained on the basis of Mendel's Law of Dominance?

(1) The discrete unit controlling a particular character is called a factor

(2) Out of one pair of factors one is dominant, and the other is recessive

(3) Alleles do not show any blendings and both the characters recover as such in F₂ generation.

(4) Factors occur in pairs

The genotype of a plant showing the dominant phenotype can be determined by

(1) test cross

(2) dihybrid cross

(3) pedigree analysis

(4) back cross

ABO blood groups in humans are controlled by the gene I. It has three alleles — I^A, I^B and i. Since there are three different alleles, six different genotypes are possible. How many phenotypes can occur?

(1) Three

(2) One

(3) Four

(4) Two

Select the correct statement from the ones given below with respect to dihybrid cross.

(1) Tightly linked genes on the same chromosome show higher recombinations

(2) Genes far apart on the same chromosome show very few recombinations

(3) Genes loosely linked on the same chromosome show similar recombinations as the tightly linked ones

(4) Tightly linked genes on the same chromosome show very few recombinations.

Which one of the following symbols and its representation, used in human pedigree analysis is correct?

(1) = Marriage between relatives

(2) = Unaffected male

(3) = Unaffected female

(4) = Male affected

Sickel cell anaemia is

(1) an autosomal linked dominant trait 

(2) caused by substitution of valine by glutamic acid in the β-globin chain of haemoglobin.

(3) caused by a change in base pair of DNA

(4) characterized by elongated sickle like RBCs with a nucleus. 

Study the pedigree chart given below

What does it show?