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CIE iGCSE Co-Ordinated Science B13.3 Homeostasis Exam Style Questions Paper 3

CIE iGCSE Co-Ordinated Science Paper 3 - All Chapters

Question

(a) Fig. 7.1 shows a cross-section through human skin.
(i) Table 7.1 shows some information about two of the parts labelled in Fig. 7.1. Complete Table 7.1.
(ii) A human has a fat layer in the skin of 3 cm.
A whale has a fat layer in the skin of 50 cm.
Explain why whales are better adapted to a cold environment.
(b) Tick (✓) two boxes to show the role of the brain in the maintenance of internal body temperature.
(c) State the word that is used to describe the maintenance of a constant internal environment.

Most-appropriate topic codes (Cambridge IGCSE Co-ordinated Sciences 0654):

• Topic B13.3 — Homeostasis: skin structure and temperature control (Parts (a), (b))
• Topic B13.3 — Homeostasis (Part (c))

▶️ Answer/Explanation

(a)(i)

Label A points to the coiled gland in the lower skin layer, which is the sweat gland responsible for producing sweat.
Label B points to the small muscle attached to the hair follicle, the hair erector muscle, which contracts to make the hair stand up.

(a)(ii) Whales have a much thicker fat layer, which provides better insulation, reducing heat loss to the cold surroundings

Fat is a poor conductor of heat and acts as an insulating layer.
Since the whale’s fat layer (50 cm) is far thicker than the human’s (3 cm), it insulates much more effectively, reducing heat loss in cold water.

(b) Tick: 

The brain (hypothalamus) detects changes in blood temperature using its own receptors.
It also coordinates the body’s responses (such as sweating or shivering) to restore normal temperature, so these are the two roles directly performed by the brain.

(c) Homeostasis

The maintenance of a constant internal environment in the body is given a specific term.
This term is homeostasis.

Question

(a) Fig. 7.1 shows a cross‐section through human skin.

(i) Table 7.1 shows some information about two of the parts labelled in Fig. 7.1.
Complete Table 7.1.

(ii) A human has a fat layer in the skin of 3cm.
A whale has a fat layer in the skin of 50cm.
Explain why whales are better adapted to a cold environment.

………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….

(b) Tick (√) two boxes to show the role of the brain in the maintenance of internal body temperature.

(c) State the word that is used to describe the maintenance of a constant internal environment.
…………………………………………………………………………………………………………………………… 

▶️Answer/Explanation

Ans :  7(a)(i)

7(a)(ii) whales have a thicker fat layer ;

fat provides insulation / ref to insulator etc ;

7(b)

7(c) homeostasis ;

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