English Medium कक्षा १० - CBSE Question Bank Solutions for Science

The change in focal length of an eye lens is caused by the action of the ______.

List two differences in tabular form between dominant trait and recessive traits. What percentage/proportion of the plants in the F₂ generation/progeny were round, in Mendel's cross between round and wrinkled pea plants?

"It is possible that a trait is inherited but may not be expressed." Give a suitable example to justify this statement.

If we pure-bred tall (dominant) pea plant with pure-bred dwarf (recessive) pea plant we will get pea plants of F₁ generation. If we now self-cross the pea plant of F₁ generation, then we obtain pea plants of F₂ generation.

(a) What do the plants of F₂ generation look like?

(b) State the ratio of tall plants to dwarf plants in F₂ generation.

(c) State the type of plants not found in F₁ generation but appeared in F₂ generation, mentioning the reason for the same.

Explain Mendel’s law of independent inheritance. Give one example.

Mendel, in one of his experiments with pea plants, crossed a variety of pea plant having round seeds with one having wrinkled seeds. State Mendel’s observations giving reasons of F₁ and F₂ progeny of this cross. Also, list any two contrasting characters, other than round seeds of pea plants that Mendel used in his experiments.

Answer the following question.
Name the plant Mendel used for his experiment. What type of progeny was obtained by Mendel in F₁ and F₂ generations when he crossed the tall and short plants? Write the ratio he obtained in F₂ generation plants.

Why are the traits acquired during the life time of an individual not inherited? Explain.

What is genetics?

Having two eyes facilitates in

A: Increasing the field of view

B: Bringing three-dimensional view

C: Developing the concept of distance/size

Then the correct option is/are

Near and far points of a young person normal eye respectively are:

The ability of the eye lens to adjust its focal length to form a sharp image of the object at varying distances on the retina is called:

The focal length of the eye lens increases when eye muscles ____________.

The least distance of distinct vision for a normal eye is ____________.

A student sitting on the last bench can read the letters written on the blackboard but is not able to read/the letters written in his textbook. Which of the following statements is correct?

In humans, if gene B gives brown eyes and gene b gives blue eyes, what will be the colour of eyes of the persons having combinations 
(i) Bb and (ii) BB?

What will be the number of chromosomes present in each gamete produced by the plants if the palisade cells of a species of the plant contain 28 chromosomes in all?

Assertion: When pure breed tall plants are crossed with pure breed short plants, all the plants in F₁ progeny are tall. When the tall plants of F₁ progeny are crossed, short plants re-appear in F₂ progeny.

Reason: Traits are independently inherited.

Two pink coloured flowers on crossing resulted in 1 red, 2 pink and 1 white flower progeny. The nature of the cross will be

A cross between a tall plant (TT) and short pea plant (tt) resulted in progeny that were all tall plants because