Question

Given below are two statements:
Statement I: A heat unit is the departure from the mean daily temperature below the maximum temperature.
Statement II: \(Q_{10}\) is the ratio of the rate of a process at a certain temperature to that at a temperature \(10^{\circ}C\) lower.
In light of the above statements, choose the most appropriate answer from the options given below:

• A. Both Statement I and Statement II are true
• B. Both Statement I and Statement II are false
• C. Statement I is correct but Statement II is false
• D. Statement I is incorrect but Statement II is true

Hint:

Heat units (GDD):
- GDD = (Tmax + Tmin)/2 - Tbase.
- \(Q_{10}\): Temperature coefficient for reaction rates.
- \(Q_{10}\) is often ~2 for biological processes.

Answer 1

The Correct Option is D

Step 1: Understanding the Question:
This question tests knowledge of heat units and temperature coefficients.

Step 2: Detailed Explanation:
A heat unit (growing degree day) is the accumulation of temperature above a base temperature (not the maximum).
It is calculated as: (Tmax + Tmin)/2 - Tbase.
Thus, Statement I is incorrect.
\(Q_{10}\) is the factor by which a reaction rate increases for a \(10^{\circ}C\) rise in temperature.
It is defined as the ratio of the rate at a higher temperature to that at a temperature \(10^{\circ}C\) lower.
Thus, Statement II is correct.
Therefore, Statement I is incorrect but Statement II is true.

Step 3: Final Answer:
Thus, Statement I is incorrect but Statement II is true, which corresponds to option (D).
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