Which line system on Earth is considered to have no significant influence on climate conditions?

Longitude is indeed considered to have no significant influence on climate conditions, primarily because it represents the east-west position on the Earth's surface rather than any geographical feature that affects weather patterns. While latitude plays a crucial role in determining climate by influencing the angle of sunlight received and prevailing atmospheric conditions, longitude does not have the same impact.

Latitude is essential in understanding climate because it helps in determining temperature ranges and seasonal variations, with areas closer to the equator generally experiencing warmer climates year-round. The Equator and the Tropic of Capricorn are specific latitudes that also denote significant climate zones, such as tropical and subtropical regions, which further illustrate the influence of latitude on climate.

In contrast, longitude primarily serves as a way to determine time zones and does not directly affect temperature, precipitation, or other climate variables in the way that latitude does. Thus, the absence of a climatic influence from longitude is a key reason why it is the correct choice in this question.