Which statement about rainforests is true?

Rainforests are critical ecosystems that are known for their rich biodiversity and significant role in the global environment. The statement that they cover six percent of the earth is accurate; in fact, tropical rainforests alone account for about six percent of the Earth's total land area. This coverage is essential as it underscores the vast and dense nature of these forests, which play a crucial role in carbon storage, climate regulation, and providing habitat for countless species.

In contrast, while rainforests do host a significant portion of the Earth’s biodiversity, claiming they contain a third of all species is an exaggeration. It’s important to recognize that they are primarily found near the equator, particularly in regions known as tropical zones, rather than in polar regions where conditions are not conducive to rainforest growth. Moreover, stating they cover ten percent of the Earth also overestimates their actual coverage. Therefore, the correct statement emphasizes the precise understanding of their extent on Earth's surface.