In human ABO blood grouping possible number of genotypes is

(1) 3

(2) 4

(3) 6

(4) 9

Recessive character is expressed in

(1) F0

(2) F1

(3) F2

(4) Never expressed.

Our ancestors knew about the inheritance of characters and variations because-

(1) They selectively breed plants and animals and selected for organisms that possessed desirable characters.

(2) They introduced mutations

(3) They performed natural hybridisation

(4) All of the above

Monohybrid cross can be defined as

(1) Cross between plants differing in one chromosome

(2) Cross between plants differing in one character only

(3) Cross between plants differing in two traits

(4) All of the above

Types of gametes produced by a homozygous parent

(1) many

(2) single type

(3) depends upon number of genes

(4) depends upon number of chromosomes

If a man consists of an extra copy of chromosome number 18, then the condition is known as

1. Monosomy

2. Trisomy

3. Nullisomy

4. Polyploidy

Disorder caused by the trisomy of chromosome number 21

(1) Klinefelter’s syndrome

(2) Turner’s syndrome

(3) Down’s syndrome

(4) Phenylketonuria

Down’s syndrome was first described in the year

(1) 1962

(2) 1866

(3) 1856

(4) 1863

Gynaecomastia refers to

1. Masculine development in females

2. Development of breasts in males

3. Development of female characters in male

4. Reduced breasts in the female

In humans karyotype of 47, XXY leads to  

(1) Klinefelter’s syndrome

(2) Turner’s syndrome

(3) Down’s syndrome

(4) Edward’s syndrome