Solved 2023 Question Paper ICSE Class 10 Biology
Solutions for Biology, Class 10, ICSE
Section A
20 questionsAnswer:
Flowers
Reason — Biodegradable waste refers to organic materials that can be broken down naturally by microorganisms and environmental processes. Flowers are a type of organic waste that can decompose over time, making them biodegradable whereas metal cans, e-waste, plastic are non-biodegradable waste.
Answer:
Semilunar valves close
Reason — 'Dup' sound is produced at the beginning of ventricular diastole when the semilunar valve at the root of aorta and pulmonary artery close.
Answer:
Tap water
Reason — When plasmolysed cell is placed in Tap water (hypotonic solution), the cell absorbs water and becomes normal. This is known as deplasmolysis.
Answer:
Cobalt chloride paper
Reason — Cobalt chloride paper turns from blue to pink when exposed to moisture. Hence, it is used to demonstrate unequal transpiration in a dicot leaf.
Answer:
DNA is synthesised
Reason — During the synthesis phase (S phase) of the cell cycle, the primary focus is on the synthesis of DNA. This phase is when the cell replicates its DNA in preparation for cell division.
Name the following:
(i) The organelle that forms the aster during cell division.
(ii) A genetic disorder in which the blood does not clot.
(iii) The permanent stoppage of menstruation in human females around the age of 45 years.
(iv) The openings on the barks of trees through which transpiration occurs.
(v) A gaseous plant hormone which promotes ripening of fruits.
Answer:
(i) Centriole
(ii) Hemophilia
(iii) Menopause
(iv) Lenticels
(v) Ethylene
Arrange and rewrite the terms in each group in correct order to be in a logical sequence beginning with the term that is underlined:
(a) Snake, Rabbit, Cabbage, Hawk.
(b) Xylem, Soil water, Cortical cells, Root hair.
(c) Receptor, Response, Effector, Spinal Cord.
(d) Fovea, Lens, Cornea, Conjunctiva.
(e) Testis, Urethra, Sperm duct, Epididymis.
Answer:
(a) Cabbage → Rabbit → Snake → Hawk.
(b) Soil water → Root hair → Cortical cells → Xylem
(c) Receptor → Spinal Cord → Effector → Response
(d) Conjunctiva → Cornea → Lens → Fovea
(e) Testis → Epididymis → Sperm duct → Urethra
Match the items given in Column I with most appropriate ones in Column II and rewrite the correct matching pairs:
Column I | Column II |
---|---|
Hyposecretion of Thyroxine in adults | Diabetes insipidus |
Hyposecretion of Insulin | Myxoedema |
Hypersecretion of Growth hormone in childhood | Dwarfism |
Hyposecretion of ADH | Gigantism |
Hypersecretion of Thyroxine | Diabetes mellitus |
Exophthalmic goitre | |
Cretinism |
Answer:
Column I | Column II |
---|---|
Hyposecretion of Thyroxine in adults | Myxoedema |
Hyposecretion of Insulin | Diabetes mellitus |
Hypersecretion of Growth hormone in childhood | Gigantism |
Hyposecretion of ADH | Diabetes insipidus |
Hypersecretion of Thyroxine | Exophthalmic goitre |
Choose the odd one out from the following terms and name the category to which the others belong:
(a) Used bandages, Pesticides, Face masks, Syringes.
(b) Dust, Smoke, Carbon monoxide, Effluents
(c) Uterus, Urethra, Urinary bladder, Ureter
(d) Menstrual phase, Telophase, Follicular phase, Luteal phase
(e) Malleus, Incus, Cochlea, Stapes
Answer:
(a) Odd one : Pesticides
Used bandages, Face masks, Syringes — Bio-medical wastes
(b) Odd one : Effluents
Dust, Smoke, Carbon monoxide — Air pollutant
(c) Odd one : Uterus
Urethra, Urinary bladder, Ureter — Parts of Excretory System
(d) Odd one : Telophase
Menstrual phase, Follicular phase, Luteal phase — Menstrual cycle
(e) Odd one : Cochlea
Malleus, Incus, Stapes — Ear ossicles
Answer:
(a) Thyroid gland → Infront of neck below larynx.
(b) Dura mater → The outermost membrane covering the brain directly under skull.
(c) Amniotic fluid → In the space between the amnion and the embryo.
(d) Papillary muscles → Lower portion of the interior walls of the ventricles.
(e) Islets of Langerhans → Pancreas.
Section B
30 questionsAnswer:
Two functions of blood are:
- Transport of digested food (in the form of simple sugars like glucose, amino acids, vitamins, mineral salts, etc.) from the alimentary canal to the tissues.
- Transport of oxygen from the lungs to the tissues by means of haemoglobin present in red blood cells.
Answer:
Karyokinesis | Cytokinesis |
---|---|
It is the division of the nucleus. | It is the division of the cytoplasm. |
It is the first division. | It occurs after karyokinesis. |
It results in the formation of two nuclei. | It results in the formation of two daughter cells. |
Answer:
Excessive use of fertilizers in agricultural fields leads to accumulation of unused chemicals in soil. The soil becomes either acidic or basic, making the soil unfit for cultivation. Also the beneficial microorganisms present in the soil are killed due to chemicals and disturbed ph of soil. Therefore, excessive use of fertilizers in agricultural fields reduces the yield of crops.
Study the diagram given below and answer the questions that follow:

(a) Name the phenomenon depicted by the shoot in the above diagram.
(b) Which plant hormone plays an important role in the above movement?
(c) Complete and rewrite the given statement by filling in the correct terms:
Shoots show positive ............... whereas, roots show positive ............... .
Answer:
(a) Phototropism
(b) Auxin
(c) Shoots show positive phototropism whereas, roots show positive geotropism .
Answer:
Law of Segregation (also called the law of purity of gametes) — The two members of a pair of factors separate during the formation of gametes. They do not blend but segregate or separate into different gametes. The gametes combine together by random fusion at the time of zygote formation.
Answer:
(a) Global warming
(b) Green house effect due to accumulation of greenhouse gases like Carbon dioxide (CO2) and Methane (CH4) in the atmosphere.
(c) To prevent global warming, use of fossil fuels should be minimized and renewable energy sources should be adopted rapidly. Deforestation should be stopped and more trees should be planted.
Answer:
Testes are responsible for the production of male gametes i.e., sperms. The normal body temperature does not allow the maturation of the sperms. Being suspended outside the body cavity, the temperature in the scrotal sac is 2 to 3°C lower than that of the body which is the suitable temperature for the maturation of the sperms.
Answer:
The Bowman's capsule and the proximal convoluted part of all the nephrons lie in the cortex of kidneys giving it a dotted appearance. Henle's loops and collecting ducts lie in the renal medulla giving it a striped appearance.
A potted plant with variegated leaves was kept in dark for 24 hours and then placed in bright sunlight. Answer the following questions.

(a) Which aspect of photosynthesis is being tested in the above diagram?
(b) Why was the plant kept in dark for 24 hours?
(c) After the starch test what will be the colour of the yellow and green parts of the leaf? Give reasons to support your answer.
Answer:
(a) Presence of chlorophyll is necessary for photosynthesis.
(b) The plant is kept in dark for 24 hours to to destarch the leaves.
(c) After conducting the starch test, the green leaf portion turns blue, indicating starch presence, confirming photosynthesis due to chlorophyll. Non-green parts lack chlorophyll, don't photosynthesize, and show no starch-related colour change.
Answer:
R | r | |
R | RR | Rr |
r | Rr | rr |
Phenotypic Ratio: 3:1
RR,Rr will be red flowering and rr will be white flowering plant.
Genotypic Ratio: 1:2:1
RR(Dominant homozygous), Rr (Dominant heterozygous), rr(Recessive homozygous)
Answer:
On a bright sunny day, the rate of transpiration is much higher than any other days. The leaves of certain plants roll up on a bright sunny day to reduce the exposed surface and thus reduce the rate of transpiration.
Answer:
A semipermeable membrane is a membrane which allows the passage of molecules selectively. It allows a solvent such as water molecules to pass through it freely but prevents the passage of the solute (sugar or salt molecules in solution).
Cell membrane is the semi permeable membrane present in the plant cell.
Answer:
(a) Ventricles are in contraction phase
(b) Blood is passing into aorta and pulmonary artery through semilunar valves.
(c) Difference between Systole and Diastole:
Systole | Diastole |
---|---|
Systole refers to contraction phase of the heart. | Diastole refers to expansion phase of the heart. |
Systole consists of contraction of auricles followed by contraction of ventricles. | Diastole consists of relaxation of ventricles immediately followed by relaxation of auricles. |