Question 191 markMCQSection A

$Assertion (A): Blood clotting prevents excessive loss of blood. Reason (R): Blood clotting is due to blood plasma and white blood cells present in the blood.$

Life Processes

Transportation in Human Beings

Options

(a)

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

(b)

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

(c)

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

(d)

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

Official answer

c

blood clotting

platelets

white blood cells

prevent blood loss

Marking scheme

1. $1 mark for correctly identifying that Assertion is true but Reason is false (option c).$

Hint

$Identify which cellular component of blood is specifically responsible for clotting at the site of injury. Is it white blood cells or platelets?$

Quick oral answer

$Blood clotting is caused by blood platelets, which help plug leaks at the site of injury to prevent excessive blood loss. White blood cells are involved in immunity, not clotting.$

Common mistakes

1. $Students often confuse the functions of different blood cells, thinking white blood cells or general plasma components are responsible for clotting, whereas platelets play the primary role in forming a plug.$

Analysis and explanation

The correct option is (c). Assertion (A) is true: Blood clotting is a vital defense mechanism that plugs leaks and prevents excessive blood loss from the body during an injury. Reason (R) is false: Blood clotting is primarily mediated by specialized cell fragments called platelets (thrombocytes) present in the blood, not by white blood cells (WBCs). White blood cells are responsible for fighting infections and immune defense.

Interesting facts

$Platelets release clotting factors that convert soluble fibrinogen in the plasma into insoluble fibrin threads, forming a mesh that traps red blood cells to create a clot.$

Question details

Q19 of 39 questions

Board: CBSE
Class: Class 10
Subject: Science
Year: 2023
Section: Section A
Marks: 1
Type: MCQ
Chapter: Life Processes
Topic: $Transportation in Human Beings$
Bloom's level: Analyzing
Syllabus topic: $Blood Platelets and Clotting$

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Frequently asked questions

$How many marks does this question carry in CBSE Class 10 Science 2023?$

$This question carries 1 mark in the CBSE Class 10 Science 2023 examination.$

$Which chapter does this question come from in Science?$

$This question is from the chapter "Life Processes" in the CBSE Class 10 Science syllabus.$

$What topic does this question cover in Science?$

$This question covers the topic "Transportation in Human Beings" from CBSE Class 10 Science.$

$What type of question is this in the CBSE Class 10 Science 2023 paper?$

$This is a MCQ question from Section A in the CBSE Class 10 Science 2023 paper.$