List of top Science Questions on Life Processes asked in CBSE Class X, CBSE Compartment X

Assertion : In human beings, the respiratory pigment is haemoglobin present in red blood cells.
Reason (R) : Haemoglobin has a very high affinity for carbon dioxide.
What is the function of diaphragm in human respiratory system ? Where is it present in human body ?
When a human egg is fertilized by a sperm having ‘Y’ chromosome, the zygote has the following combination of chromosomes:
Which of the following is a non-biodegradable pollutant?
Choose the equation of reaction that correctly represents anaerobic respiration in muscles:
Name the device used for measuring electric current. How is it connected in a circuit ?
How many bulbs of resistance \( 8 \ \Omega \) each should be connected in parallel combination to draw a current of \( 2 \text{ A} \) from a battery of \( 4 \text{ V} \) ?
Conductors of electric toasters and electric iron are made of an alloy rather than a pure metal. Why ?
A person is unable to read a book placed closer than \( 1 \text{ meter} \) from his eyes. Identify the defect of vision in his eyes. Draw the ray diagrams to show the defect of vision and its correction.
Give one example each of electrolytic decomposition and decomposition by sunlight.
Balance the following chemical reaction: \( Pb(NO_3)_2 + KI \longrightarrow PbI_2 + KNO_3 \)
In a bisexual flower the male gametes are present in the :
Assertion (A) : In large animals, oxygen can reach different parts of the animal's body easily.
Reason (R) : Respiratory pigments take up oxygen from the air and carry it to body tissues.
The basic filtration unit of the excretory system in human beings is:
Which one of the following is not an excretory product in plants?
In human alimentary canal, the digestive juice secreted by the gastric glands are:
Consider the following food chain:
Grass \( \rightarrow \) Grasshopper \( \rightarrow \) Frog \( \rightarrow \) Snake \( \rightarrow \) Eagle
If the amount of energy available at third trophic level is 50 kJ, the available energy at the producer level was:
In human female reproductive system state the changes that take place once fertilisation has taken place. Write the role of placenta in this process. What happens when the egg is not fertilised ?
Name the parts marked as 'A' and 'B' in the given diagram. Write in detail the changes that take place in a flower when the product of 'B' reaches 'A' till a fruit is formed.
parts marked as ’A’ and ’B’
What is the first step of cellular respiration? In which part of the cell does it occur ? Write the equation for the process of breakdown of glucose in a human cell : (i) in the presence of oxygen (ii) due to lack of oxygen
Explain with the help of a flow chart that in human beings father is responsible for the sex (male or female) of the child.
Name the tissues which form the vascular bundle. State their function in plants.
Name the blood vessel that brings (i) oxygenated blood (ii) deoxygenated blood to the human heart. Also name that chamber of the heart which receives deoxygenated blood and state how deoxygenated blood from this chamber is sent to lungs for oxygenation.
Explain why respiration is considered an exothermic reaction. Give the chemical equation for this reaction.
The part of a seed that stores food, the future root, and the future shoot respectively are: