Science 31/2/1 2025-2026 English Medium Class 10 Question Paper Solution

The genotype of green stemmed tomato plant is denoted by ‘GG’ and that of purple stemmed tomato plant as ‘gg’. Hybrid of a cross between these two were self-pollinated to obtain F₂ progeny. What will be the ratio of GG, Gg and gg in this F₂ progeny?

2 : 1 : 1

3 : 1 : 0

1 : 1 : 2

1 : 2 : 1

Identify the type of tropic movement that is responsible for the movement of the pollen tube towards an ovule from the following options.

Hydrotropism

Geotropism

Chemotropism

Phototropism

Spirogyra, despite being a multi-cellular organism, still shows a simple reproductive method. Select the correct option with regard to reproduction in Spirogyra:

Asexual reproduction by division of cells into two cells.

Sexual reproduction by division of cells into many cells.

Asexual reproduction by breaking up of Spirogyra filaments into smaller parts

Sexual reproduction by the formation of gametes after meiosis of cells of filaments followed by fusion of male and female gametes.

The carbohydrates, which are not used immediately in plants, are stored in the form of ‘a’, which serves as an internal energy reserve. What does ‘a’ stand for?

Starch

Sugar

Fat

Protein

The following events occur during the process of photosynthesis. Choose the option that indicates the correct events.

1. Oxidation of carbon dioxide to carbohydrates.
2. Conversion of light energy into chemical energy.
3. Absorption of light energy by chlorophyll.
4. Conversion of hydrogen and oxygen into water.

(i) and (ii)

(ii) and (iii)

(iii) and (iv)

(i) and (iv)

In the given figure, identify the trophic level having maximum concentration of harmful chemicals.

T1

T5

T4

T3

Which of the following limits the number of trophic levels in a food chain?

Availability of water

Deficient food supply

Decrease in energy at higher levels

Pollution in air

Assertion (A): Blood plasma transports carbon dioxide in dissolved form, while oxygen is transported by respiratory pigments.

Reason (R): Carbon dioxide is more soluble in water than in oxygen.

Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).

Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of Assertion (A).

Assertion (A) is true, but Reason (R) is false.

Assertion (A) is false, but Reason (R) is true.

Assertion (A): There are generally a greater number of individuals at the lower trophic levels of an ecosystem.

Reason (R): The greatest number is of the producers.

Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).

Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of Assertion (A).

Assertion (A) is true, but Reason (R) is false.

Assertion (A) is false, but Reason (R) is true.

“The timing and the amount of hormone secreted by a gland are regulated in the human body.” Justify this statement with the help of an example.

Electrical impulse is an excellent means to transmit information in the animal body, but there are some limitations to the use of electrical impulses. State any two limitations.

“Variation is useful for the survival of species over time.” Explain this statement with the help of an example.

Suggest one best way to dispose of the following waste:

Kitchen waste

Suggest one best way to dispose of the following waste:

Metallic waste

Suggest one best way to dispose of the following waste:

Plastic bottles

Suggest one best way to dispose of the following waste:

Sanitary waste

Complete the pathways given below, showing the breakdown of glucose.

Identify ‘A’, ‘B’, ‘C’, ‘D’, ‘E’ and ‘F’.

Giving two examples, justify the statement that the sex of the offspring in all animals is not always genetically determined.

Differentiate between the sex chromosomes of male and female human beings.

Read the following passage and answer the questions that follow:

(a) What are voluntary actions?    [1]

(b) Which part of the brain is responsible for precision of voluntary actions?    [1]

(c) (i) Explain the role of the medulla.    [2]

OR

(c) (ii) How do the animal muscles move?    [2]

Name an organ that helps in the formation of male germ cells in humans and also mention the condition that favours the formation of male germ cells.

In male reproductive system, write the pathway followed to deliver male germ cells to the site of fertilisation.

Mention the main physical feature of the male germ cell that helps it move towards the female germ cell.

Radha has three children. She does not want to have more children. Radha visits a nearby hospital, to know the methods to prevent pregnancy.

1. Mention the name of any two ways other than the surgical methods, following which Radha can avoid unwanted pregnancies.
2. Name the surgical methods to prevent pregnancy.
3. Give one example each of sexually transmitted diseases caused by bacteria and virus.

Which of the following are combination reactions?

1. \[\ce{2KClO3 -> 2KCl + 3O2}\]
2. \[\ce{MgO + H2O -> Mg(OH)2}\]
3. \[\ce{4Al + 3O2 -> 2Al2O3}\]
4. \[\ce{Zn + FeSO4 -> ZnSO4 + Fe}\]

(i) and (iii)

(iii) and (iv)

(ii) and (iv)

(ii) and (iii)

A metal carbonate reacts with a solution X which forms a salt, water and a gas Y. What are X and Y?

X - Sodium hydroxide, Y - Carbon dioxide

X - Sodium hydroxide, Y - Hydrogen

X - Hydrochloric acid, Y - Carbon dioxide

X - Hydrochloric acid, Y - Hydrogen

When ferrous sulphate crystals are heated in a test tube, we observe that ______.

A colourless gas with no smell is evolved.

A brown gas is evolved.

The green colour of the salt fades and a gas with the smell of burning sulphur is evolved.

The green colour of the salt fades and no gas is evolved.

When Mg metal is treated with hot water, it starts floating on the surface of the water. The reason for its different behaviour is:

Mg is a lighter element than water.

Mg reacts with water to produce H₂ gas which helps in floating.

Mg reacts with water to produce N₂ gas which helps in floating.

Mg reacts with water to form CO₂ gas which helps in floating.

The pH of the gastric juices released during digestion is ______.

less than 7

more than 7

equal to 7

equal to 0

Baking powder is a mixture of ______.

Sodium carbonate + Acetic acid

Sodium carbonate + Tartaric acid

Sodium hydrogen carbonate + Tartaric acid

Sodium hydrogen carbonate + Acetic acid