LIWA

Life Processes

CBSE Class 10 · Science · Chapter 5

Past board exam questions

CBSE 2027 sample paper · 1 mark

During photosynthesis, what happens to carbon dioxide and water as glucose is formed?

  1. Carbon dioxide gains hydrogen, while water loses electrons.
  2. Carbon dioxide loses oxygen, while water gains oxygen.
  3. Carbon dioxide is oxidised, while water is reduced.
  4. Both carbon dioxide and water undergo reduction.
Show answer
Carbon dioxide gains hydrogen, while water loses electrons.

CBSE 2027 sample paper · 1 mark

Lime water turns cloudy in the presence of a gas, which is a by-product of respiration. Shown below are four setups kept in sunlight for 24 hours. In which setup is lime water expected to be the cloudiest? Set P: a glass tank covering a pot with no plant and a dish of limewater. Set Q: a glass tank covering a pot with a plant and a dish of limewater. Set R: a tank coated with black paint covering a pot with a plant and a dish of limewater. Set S: a tank coated with black paint covering a pot with no plant and a dish of limewater.

  1. P
  2. Q
  3. R
  4. S
Show answer
R

CBSE 2027 sample paper · 1 mark

During urine formation, tubular reabsorption and secretion take place in the kidneys. Which of the following sets correctly indicates both the substances that are reabsorbed in the kidneys?

  1. Glucose and salts
  2. Glucose and starch
  3. Glycogen and salts
  4. Glycogen and starch
Show answer
Glucose and salts

CBSE 2027 sample paper · 1 mark

Assertion (A): The rate of breathing in aquatic organisms is much lower than in the terrestrial organisms. Reason (R): The amount of oxygen dissolved in water is less as compared to the amount of oxygen in air.

  1. Both A and R are true, and R is the correct explanation of A.
  2. Both A and R are true, and R is not the correct explanation of A.
  3. A is true but R is false.
  4. A is false but R is true.
Show answer
A is false but R is true.

CBSE 2027 sample paper · 2 marks

A. Due to narrowing of the bile duct, the bile secretion from the liver to the small intestine was obstructed. How will the process of digestion be affected? B. How does the length of the intestine depend on the nature of food habit in different animals?

Show answer
A. Bile juice from the liver makes the food coming from the stomach alkaline so that the pancreatic enzymes can act. Bile salts also break fats down into smaller globules (emulsification), increasing the efficiency of enzyme action. If the bile duct is obstructed, the food stays acidic and fats are not emulsified, so digestion of fats will be improper. B. Herbivores eating grass need a longer small intestine to allow the cellulose to be digested. Meat is easier to digest, hence carnivores like tigers have a shorter small intestine.

CBSE 2026 sample paper · 1 mark

Select the group in which all organisms have the same mode of nutrition.

  1. Cuscuta, yeast, legumes, leeches and tapeworm
  2. Cactus, ticks, lice, leeches and cow
  3. Cuscuta, ticks, lice, leeches and tapeworm
  4. Cactus, grass, lice, lion and tapeworm
Show answer
Cuscuta, ticks, lice, leeches and tapeworm

CBSE 2026 board paper · 1 mark

Which structure in a leaf is mainly responsible for gaseous exchange ?

  1. Xylem
  2. Stomata
  3. Phloem
  4. Cuticle
Show answer
Stomata

CBSE 2026 board paper · 1 mark

Pravin was given a list of characteristics associated with the process of anaerobic respiration in humans, in the table given below : | | Location | Condition | End Product | |---|---|---|---| | Characteristic | (i) Muscle Cell | (ii) Requires presence of Oxygen (O2) and Carbon dioxide (CO2) | (iii) 3-Carbon molecules | Which of the above characteristics is/are related to the above process ?

  1. (i) and (ii)
  2. (i) and (iii)
  3. (ii) and (iii)
  4. (i) only
Show answer
(i) and (iii)