Home / IB DP Biology- D3.3 Homeostasis – IB Style Questions For SL Paper 1A

IB DP Biology- D3.3 Homeostasis - IB Style Questions For SL Paper 1A -New Syllabus

IBDP Biology Paper 1 - All Chapters

Question

These results were obtained by measuring the body temperature of people exercising on a hot and humid day. What mechanism could result in the changes seen during the rest periods?

(A) Shivering
(B) Uncoupled respiration in brown adipose tissue
(C) Vasodilation in the skin
(D) Hair erection
▶️ Answer/Explanation

Correct Answer: \( \boxed{\mathbf{C}} \)

During the rest periods, body temperature decreases because vasodilation increases blood flow to the skin, allowing more heat to be lost to the surroundings. This cooling mechanism helps return body temperature toward its normal range after exercise.

Question

Which row below provides the correct combination of gland, hormone, and its main action in the endocrine system?
OptionGlandHormoneAction
Apinealmelatonincontrols circadian rhythm
Badrenalepinephrine (adrenaline)controls circadian rhythm
Cadrenalmelatoninprepares the body for vigorous activity
Dpinealepinephrine (adrenaline)prepares the body for vigorous activity
▶️ Answer/Explanation
Detailed solution

The pineal gland produces melatonin, a hormone that helps regulate the body’s circadian rhythm. This makes row A the only correct match. ✅ Answer: (A)

Question

The diagram shows the structure of human skin.

Skin diagram

What are X, Y and Z?

Skin labels table
▶️ Answer/Explanation

Answer: C

Identifying structures:

X:
• X points to a coiled tube deep in the dermis.
• This is the characteristic shape and location of a sweat gland.

Y:
• Y attaches to the side of the hair follicle at an angle.
• This is the hair erector muscle (arrector pili), responsible for goosebumps.

Z:
• Z is a long, thin structure connected to a receptor ending.
• This represents a sensory neurone carrying impulses from skin receptors.

Correct Matching:

LabelStructure
XSweat gland
YHair erector muscle
ZSensory neurone

✅ Answer: C

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