List of top Science Questions on Genetics and Evolution asked in CBSE Class X

Mendel took garden pea plants with different characteristics, such as height to study the inheritance pattern of factors (genes). He crossed tall pea plant with short pea plant and obtained all the tall plants in the F1 generation. 

When a pure-tall pea plant is crossed with a pure-dwarf pea plant, the percentage of tall pea plants in F1 and F2 generation pea plants will be respectively:

Explain the mechanism of inheritance used by sexually reproducing organisms to ensure the stability of DNA of the species. 

A tall pea plant with round seeds (TTRR) is crossed with a short pea plant with wrinkled seeds (ttrr). The F1 generation will be:
Give the (i) percentage of white flowered plants and (ii) ratio of the gene combinations WW, Ww, and ww in F2 generation.

Proteins control the expression of various characters. Explain this statement by taking an example of "tallness" as a characteristic in plants

Write one difference between dominant and recessive trait.

List two observations made by Mendel in F1 generation plants.
What are surgical contraceptive methods? Give the side effect caused by this procedure.
Write any two characteristics of sperm.
What is regeneration? Give one example of an organism that shows this process and one organism that does not. Why does regeneration not occur in the latter?

Pure-tall (TT) pea plants are crossed with pure-dwarf (tt) pea plants. The pea plants obtained in F1 generation are then self-pollinated to produce F2 generation. 
(i) What do the plants of F1 generation look like? Justify your answer. 
(ii) What is the ratio of pure-tall plants to pure-dwarf plants in F2 generation?

Assertion (A): When ciliary muscles contract, eye lens becomes thin.
Reason (R): Ciliary muscles control the power of the eye lens.
In the light of the above statements, choose the most appropriate answer from the options given below:
Which one of the following has half the number of chromosomes and half the amount of DNA as compared to the non-reproductive body cells?
Assertion (A) : Each human trait is influenced by both paternal and maternal DNA.
Reason (R) : As compared to the father, the mother contributes more amount of genetic material to the child.