(A) Name the part of brain which is responsible for the following actions:

(i) Maintaining posture and balance

(ii) Beating of heart

(iii) Thinking

(iv) Blood pressure

OR

(B) Where are auxins synthesized in a plant ? Which organ of the plant shows :

(i) Positive phototropism

(ii) Negative geotropism

(iii) Positive hydrotropism

Q: (A) Name the part of brain which is responsible for the following actions: (i) Maintaining posture and balance (ii) Beating of heart (iii) Thinking (iv) Blood pressure OR (B) Where are auxins synthesized in a plant ? Which organ of the plant shows : (i) Positive phototropism (ii) Negative geotropism (iii) Positive hydrotropism

### Option (A) (i) **Maintaining posture and balance:** Cerebellum (part of the hind-brain). (ii) **Beating of heart:** Medulla (part of the hind-brain). (iii) **Thinking:** Fore-brain (specifically the cerebrum). (iv) **Blood pressure:** Medulla (part of the hind-brain). --- ### OR ### Option (B) * **Site of Auxin Synthesis:** Auxins are synthesized at the **shoot tips** (or growing tips) of a plant. * **Organs showing specific tropisms:** (i) **Positive phototropism:** **Shoot** (bends towards light). (ii) **Negative geotropism:** **Shoot** (grows upwards, away from the gravity pull of the earth). (iii) **Positive hydrotropism:** **Root** (grows towards water/moisture).

Control and Coordination

Human Brain and Plant Tropisms

Official Answer

Option (A)

(i) Maintaining posture and balance: Cerebellum (part of the hind-brain).

(ii) Beating of heart: Medulla (part of the hind-brain).

(iii) Thinking: Fore-brain (specifically the cerebrum).

(iv) Blood pressure: Medulla (part of the hind-brain).

OR

Option (B)

Site of Auxin Synthesis: Auxins are synthesized at the shoot tips (or growing tips) of a plant.
Organs showing specific tropisms:

(i) Positive phototropism: Shoot (bends towards light).

(ii) Negative geotropism: Shoot (grows upwards, away from the gravity pull of the earth).

(iii) Positive hydrotropism: Root (grows towards water/moisture).

CerebellumMedullaFore-brainShoot tipsShootRootposture and balanceinvoluntary actionsphototropismgeotropismhydrotropism

Marking Scheme

1For Option (A):
20.5 mark for identifying Cerebellum for posture and balance.
30.5 mark for identifying Medulla for beating of heart.
40.5 mark for identifying Fore-brain for thinking.
50.5 mark for identifying Medulla for blood pressure.
6For Option (B):
70.5 mark for stating shoot tips/growing tips as the site of auxin synthesis.
80.5 mark for identifying Shoot for positive phototropism.
90.5 mark for identifying Shoot for negative geotropism.
100.5 mark for identifying Root for positive hydrotropism.

Hint

For Part A, recall that involuntary actions are controlled by the hind-brain's medulla, while balance is managed by the cerebellum. For Part B, remember that shoots grow towards light and away from gravity, while roots grow towards water.

Quick Oral Answer

The cerebellum is responsible for maintaining posture and balance, while the medulla controls involuntary actions like blood pressure and heart beating. In plants, shoots show positive phototropism and negative geotropism, whereas roots show positive hydrotropism and positive geotropism.

Analysis & Explanation

Detailed Explanation:

#### Part (A):

Posture and Balance: The cerebellum, located in the hind-brain, is responsible for the precision of voluntary actions and maintaining the posture and equilibrium of the body.
Beating of Heart & Blood Pressure: These are involuntary actions. The medulla in the hind-brain controls involuntary actions such as blood pressure, salivation, vomiting, and heart beating.
Thinking: The fore-brain is the main thinking part of the brain, containing specialized areas for sensory integration, association, and decision-making.

#### Part (B):

Auxin Synthesis: Auxin is a plant hormone synthesized at the growing tips of shoots. It helps the cells grow longer.
Tropic Movements:

Positive phototropism: Growth towards light. Shoots bend towards light, showing positive phototropism.
Negative geotropism: Growth away from gravity. Shoots grow upwards, away from the earth, showing negative geotropism.
Positive hydrotropism: Growth towards water. Roots grow towards water sources, showing positive hydrotropism.

Common Mistakes

1Writing 'brain' generally instead of specific parts like 'cerebellum' or 'medulla'.
2Confusing positive and negative geotropism (roots show positive geotropism, while shoots show negative geotropism).
3Forgetting that both heart beating and blood pressure are controlled by the medulla.

Interesting Facts

The cerebellum contains about 50% of all the neurons in the entire brain, despite making up only 10% of the brain's volume!

Auxin comes from the Greek word 'auxein', which means 'to grow'.

Spotted a mistake or something unclear?

Tell us — we fix reported answers fast.

Frequently Asked Questions

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

This question carries 2 marks in the CBSE Class 10 Science 2023 examination.

Which chapter does this question come from in Science?

This question is from the chapter "Control and Coordination" in the CBSE Class 10 Science syllabus.

What topic does this question cover in Science?

This question covers the topic "Human Brain and Plant Tropisms" from CBSE Class 10 Science.

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

This is a Very Short Answer question from Section B in the CBSE Class 10 Science 2023 paper.