NCERT Class X Science Class: Chapter – 9. Heredity and Evolution – Part-10 (For CBSE, ICSE, IAS, NET, NRA 2022)

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Question 45:

In question 44, what are the combinations of character in the Progeny? What are their ratios?


(i) Round yellow — 9

(ii) Round green — 3

(iii) Wrinkled yellow — 3

(iv) Wrinkled green — 1

Question 46:

Give the basic features of the mechanism of inheritance.


(i) Characters are controlled by genes

(ii) Each gene controls one character

(iii) There may be two or more forms of the gene

(iv) One form may be dominant over the other

(v) Genes are present on chromosomes

(vi) An individual has two forms of the gene whether similar or dissimilar

(vii) The two forms separate at the time of gamete formation

(viii) The two forms are brought together in the zygote

Question 47:

Give reasons for the appearance of new combinations of characters in the progeny.


If a tall plant having homozygous genotype is crossed with a dwarf plant having homozygous genotype then the progeny will consist of tall plants with heterozygous genotype;

if the plants in progeny is crossed with each other then three tall plants will be produced and one will be a dwarf planet in the progeny.

Ratio of tall plants and dwarf plant in the progeny is 3: 1