Question

Increased levels of oxygen in the atmosphere due to photosynthesis caused rates of weathering to
increase
, which aided in the formation of
soil
.

Answer 1

Broadly correct, but with two important nuances: the effect of O2 was mainly to enable oxidative weathering (and to support aerobic life that increases both chemical and physical weathering), while other factors (CO2, climate, water, and biological activity) also control overall weathering rates.

Why and how:
- Oxygen enabled oxidative weathering of reduced minerals (e.g., Fe2+ → Fe3+, pyrite oxidation), producing iron oxides, clays and other secondary minerals that are important components of soil.
- Higher O2 supported aerobic microbes and, later, plants. Roots and organisms produce organic acids and physically break rock, greatly accelerating both chemical and physical weathering (pedogenesis).
- Photosynthetic removal of CO2 also altered climate (e.g., cooling) and hydrology, which can change weathering rates — so O2 was one piece of a larger system.

Clearer wording you can use:
- "The rise of atmospheric O2 from photosynthesis promoted oxidative weathering and supported life (roots and microbes) that accelerated rock breakdown, contributing to the development of soils."

If you want, I can expand with examples (e.g., Great Oxidation Event, mineral reactions) or a short timeline of early soil formation.