In the question below, a statement followed by two assumptions numbered I and II is given. You have to consider the statement and the following assumptions and decide which of the assumption is implicit in the statement:

Statement : One should not sleep under a tree at night.

Assumptions :

I. The falling leaves may spoil our clothes.

II. Tree gives out carbon dioxide at night which is injurious to health. 

To decide which assumption is implicit in the statement "One should not sleep under a tree at night," let's examine the assumptions presented:

The key to understanding implicit assumptions is to determine which assumption or assumptions are directly related to the reason implied by the statement.

Assumption I talks about the inconvenience of falling leaves spoiling clothes, which can be considered a minor inconvenience rather than a significant health or safety concern. It doesn't strongly relate to a compelling reason why someone should specifically avoid sleeping under a tree at night as opposed to any other time.

Assumption II directly addresses a health concern related to the natural process by which trees may emit carbon dioxide at night (instead of oxygen, as they do during the day through photosynthesis). This assumption implies a reason why sleeping under a tree at night might be expressly advised against in the statement, highlighting a change in environmental conditions that could affect human health.

Therefore, Assumption II is more directly and meaningfully implicit in the statement, as it provides a clear rationale concerning health that is specific to the nighttime.

Hence, the correct answer is "Only assumption II is implicit".