Question

The figure depicts how body temperature changes for two species (L and M) as a function of ambient temperature.Which one of the following statements about how L and M regulate temperature is correct?

• A. L and M are both homeotherms
• B. L and M are both poikilotherms.
• C. L is a homeotherm, whereas M is a poikilotherm.
• D. L is a poikilotherm, whereas M is a homeotherm.

Hint:

On a \(T_\text{body}\) vs \(T_\text{ambient}\) plot: \textbf{flat} curve \Rightarrow homeothermy; \textbf{diagonal} curve \Rightarrow poikilothermy.

Answer 1

The Correct Option is C

Step 1: Read the graph carefully.
- Curve for L is nearly \emph{horizontal}: body temperature of L stays almost constant despite changes in ambient temperature.
- Curve for M has a \emph{positive slope} (almost a 1:1 line): body temperature of M increases with ambient temperature.

Step 2: Recall definitions.
- Homeotherm: maintains a relatively constant internal temperature across a range of ambient temperatures.
- Poikilotherm: body temperature varies with ambient temperature.

Step 3: Classify L and M.
Horizontal line \Rightarrow constant \(T_b\) \Rightarrow L is homeotherm.
Sloped line \Rightarrow variable \(T_b\) \Rightarrow M is poikilotherm.

Step 4: Match with options.
Only option (C) states “L homeotherm; M poikilotherm.” Final Answer:
\[ \boxed{\text{(C) L is a homeotherm; M is a poikilotherm}} \]