Question

Arrange the below doses in a sequence that cause low to high percent deaths in a population:
(A) LD99
(B) LD25
(C) LD1
(D) LD50
Choose the correct answer from the options given below:

• A. (A), (D), (B), (C).
• B. (C), (A), (B), (D).
• C. (C), (B), (D), (A).
• D. (C), (D), (A), (B).

Hint:

The subscript number in "LD" directly tells you the percentage of deaths. Simply arrange the numbers in ascending order: $1% < 25% < 50% < 99%$, which gives the sequence C $\rightarrow$ B $\rightarrow$ D $\rightarrow$ A.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
In toxicology, "LD" stands for Lethal Dose.
The numerical subscript indicates the percentage of the experimental population that is expected to die when exposed to that specific dose of a toxicant or drug.

Step 2: Detailed Explanation:
Let us define each of the specified lethal doses based on their expected mortality rate:
- LD1 (C): The dose that causes death in exactly 1% of the exposed population. This represents the lowest mortality percentage among the options.
- LD25 (B): The dose that causes death in exactly 25% of the exposed population.
- LD50 (D): The median lethal dose, which causes death in exactly 50% of the exposed population. This is a standard measure of acute toxicity.
- LD99 (A): The dose that causes death in 99% of the exposed population, representing the highest mortality percentage.
To arrange these doses in a sequence corresponding to a low-to-high percentage of deaths: \[ \text{LD1 (C) [1%]} \rightarrow \text{LD25 (B) [25%]} \rightarrow \text{LD50 (D) [50%]} \rightarrow \text{LD99 (A) [99%]} \] This corresponds to the sequence (C), (B), (D), (A).

Step 3: Final Answer:
The correct chronological sequence is (C), (B), (D), (A), which corresponds to option (C).