ICSE Class 10 Biology Answer Key 2025: The answer key for the ICSE Class 10 Biology Exam 2025, will be released soon. This answer key will help students compare their answers and estimate their potential marks. Once the answer key is released, students can match their answers with the correct ones and evaluate their performance in the exam. This process helps students understand areas where they need improvement and where they performed well. Additionally, using the answer key allows students to learn from their mistakes and improve their preparation for future exams.
Check| ICSE Class 10 Biology Exam Analysis 2025
Check| ICSE Class 10 Biology Question Paper 2025
Importance of ICSE Class 10 Biology Answer Key 2025:
- Self-Assessment: By using the answer key, students can match their answers with the correct ones. This helps them understand which questions they answered correctly and where they went wrong. It also allows students to identify their strengths and weaknesses, enabling them to prepare better for upcoming exams. Self-assessment helps students learn from their mistakes and work on improvement, boosting their confidence.
- Transparency: The answer key brings transparency to the exam process, as students can clearly see which answers were correct and which were not. This increases students' trust in the exam results, as they know the evaluation was done fairly and accurately. The answer key also shows students how correct answers should be presented, which can be helpful for future exams.
ICSE Class 10 Chemistry Exam 2025: Key Highlights
Particulars | Details |
| Exam Name | ICSE Class 10 Biology Exam 2025 |
| Conducting Board | Council for the Indian School Certificate Examinations (CISCE) |
| Exam Date | March 24, 2025 |
| Exam Timing | 11:00 AM to 1:00 PM |
| Total Duration | 2 Hours |
| Total Marks | 80 Marks (Theory) |
| Exam Mode | Offline (Pen-Paper Mode) |
| Difficulty Level | To be updated... |
ICSE Class 10 Biology Answer Key 2025
Question 1
(i) The number of live births per thousand people per year is called:
Answer: Natality
Explanation: Natality (or birth rate) is the number of live births per 1,000 people per year. It is a crucial factor in population growth studies.
(ii) The structure that lies at the junction of the choroid and the iris and is itself a part of the choroid is called:
Answer: Ciliary Body
Explanation: The ciliary body is a part of the choroid and is located near the iris. It helps in:
- Accommodation (changing lens shape for focusing)
- Secreting aqueous humor, which maintains intraocular pressure.
(iii) Assertion & Reasoning
Assertion (A): Seminal vesicles pour an alkaline secretion into the semen as it passes through the ureter.
Reason (R): The female vagina is acidic and needs to be neutralized for sperm survival.
Answer: (A) is false and (R) is true.
Explanation:
Assertion is false because semen does not pass through the ureter; it passes through the urethra.
Reason is true because the female vagina is acidic, and seminal vesicle secretions neutralize the acidity to protect sperm.
(iv) The hormone that induces vigorous contractions of the uterus in a pregnant mother is:
Answer: Oxytocin
Explanation:
Oxytocin is a hormone released by the posterior pituitary gland. It stimulates uterine contractions during childbirth and helps in milk ejection during breastfeeding.
(v) A scientist wanted to conduct a genetic experiment on mice. He cut the tails of all the mice and made them reproduce. What will be the phenotype of the offspring?
Answer: All the offspring will have tails.
Explanation:
This experiment disproves Lamarck’s theory of inheritance (which wrongly suggested acquired traits are inherited).
Mendelian genetics states that traits are passed via genes, so offspring will still have tails regardless of whether the parents’ tails were cut.
(vi) Assertion & Reasoning
Assertion (A): A turgid plant cell is in a balanced state.
Reason (R): In a turgid cell, turgor pressure and wall pressure are equal and in the same direction.
Answer: Both (A) and (R) are true.
Explanation:
Turgor pressure (pressure exerted by the fluid inside the cell) and wall pressure (pressure exerted by the cell wall) balance each other, maintaining the cell's firmness. This keeps the plant upright and healthy.
(vii) The optimum temperature for photosynthesis is:
Answer: 25 - 35°C
Explanation:
Photosynthesis enzymes (like Rubisco) work best within 25-35°C. Too high or too low temperatures reduce enzyme activity, slowing down the rate of photosynthesis.
(viii) Ajay and Vijay are siblings. Ajay can roll his tongue while Vijay cannot. What is the genotype of their parents?
Answer: Both the parents are heterozygous dominant.
Explanation:
Tongue rolling is a dominant trait (R).
If one child cannot roll their tongue (rr), both parents must be heterozygous (Rr × Rr). This results in a 1:2:1 genotype ratio (RR:Rr:rr), meaning one child may have the recessive trait.
(ix) Assertion & Reasoning
Assertion (A): Deficiency of Antidiuretic hormone causes an increase in urination.
Reason (R): Antidiuretic hormone acts on the kidney to reabsorb water from the kidney tubules.
Answer: Both (A) and (R) are true.
Explanation:
ADH (Antidiuretic hormone, also called Vasopressin) regulates water balance by controlling kidney reabsorption.
Low ADH = More urination (Diabetes insipidus).
High ADH = Less urination (Water retention).
(x) A phase of cell division where the spindle fibers disappear is:
Answer: Telophase
Explanation:
During telophase, Spindle fibers break down. Nuclear membranes reform around chromosomes. The cell prepares for cytokinesis (final division).
(xi) Assertion & Reasoning
Assertion (A): Arachnoid layer helps in speeding up the transmission of nerve impulses along the axons.
Reason (R): Axon endings at the synapse secrete acetylene.
Answer: (A) is false, and (R) is false.
Explanation:
The Arachnoid layer does NOT speed up nerve transmission; that function is performed by the myelin sheath.
Axon endings secrete Acetylcholine (ACh), NOT Acetylene.
Correction Needed: Both (A) and (R) are incorrect.
(xii) Many nuclear power plants are constructed near water sources. They use water for cooling their machinery and release it back into the water stream. Identify the kind of pollution caused.
Answer: Thermal Pollution
Explanation:
Power plants release hot water into rivers/lakes, increasing the temperature. This reduces oxygen levels, harming aquatic life. It is called Thermal Pollution.
(xiii) Owls are nocturnal animals. They are active at night and hunt small animals for food. Owls have large eyes and can see well at night. This is due to:
Answer: Rods and Rhodopsin
Explanation:
Owls have more rod cells in their retina, which help in low light vision.
Rhodopsin is a light-sensitive pigment in rod cells that allows night vision. This makes them highly adapted to nocturnal life.
More answers will be updated here shortly!
Also Check:
ICSE Class 10 Syllabus 2024-25 (Subject-Wise PDFs)
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