When a die is thrown once, there are 6 possible outcomes, as the die has 6 faces numbered from 1 to 6. When the die is thrown twice, the total number of possible sample events can be found by multiplying the outcomes of the first throw by the outcomes of the second throw. Thus, the number of sample events is: \[ 6 \times 6 = 36 \] Therefore, the number of sample events when a die is thrown twice is 36.
The correct option is (D): \(36\)