Which step caused an aerobic atmosphere during the history of earth?
a. origin of cell membranes
b. an energetic atmosphere
c. origin of anaerobic prokaryotes
d. origin of photosynthetic prokaryotes

Always use significant figure rules. remember that these rules apply to all numbers that are measurements. if a vector that is 3 cm long represents 30 km/h, what velocity does a 5 cm long vector which is drawn using the same scale represent? a.100 km/h b.60km/h c.50km/h

How is the carbon cycle related to global warming ?

Oak and maple trees, chipmunks, white-tail deer, and black bears emerging from hibernation are all organisms that may be found in which biome