Please help me with this!!

*will mark brainliest to first correct answer* photosynthesis led to increasing levels during the later proterozoic eon? a. oxygen b. water c. carbon dioxide d. none of the above

How did the research presented in the article affect scientists' understanding of the evolution of eukaryotes

Match each description to the appropriate biome. tropical savanna desert tropical rain forest taiga tundra has sparse vegetation and very cold temperatures located near the equator and contains trees that form dense canopy layers is very hot and dry, and has plants that need little water has cold winters, heavy snowfall and is dominated by conifers has warm temperatures and is dominated by grasses