OCR GCSE Biology 2026 – 400 Free Practice Questions to Pass the Exam

Deforestation and cattle grazing in Mexico have significantly impacted the water cycle by altering the land's natural processes. Trees play a crucial role in the water cycle through a process known as transpiration, where they release water vapor into the atmosphere from their leaves. This moisture contributes to cloud formation and ultimately precipitation. When forests are cleared for agriculture or grazing, the number of trees decreases, leading to reduced transpiration. This results in less moisture available in the atmosphere, which can disrupt local rain patterns and diminish overall rainfall.

Furthermore, excessive cattle grazing can lead to soil degradation and erosion, which can reduce the soil's ability to retain water. This makes it more difficult for ecosystems to recover from droughts and affects the natural replenishment of aquifers. Together, these activities not only disturb the local ecosystem but can also lead to water scarcity issues, affecting both the environment and human populations.

Building more dams and engaging in industrial pollution could have indirect effects on the water cycle, but the direct and significant damage caused by deforestation and cattle grazing specifically disrupts the natural processes of the water cycle. Increased mineral extraction could also have environmental consequences, but its impact on the water cycle is less direct compared to the effects of deforestation and agriculture.