Which major event occurred during the Precambrian time? Landmasses were all below water.

Cyanobacteria filled the water and air with oxygen.

Trilobites became extinct.

People lived on Earth.

By the 1820s, many americans wanted to have an equal number of senators from the free states and the slave states. to achieve that, what would need to be true? sorry, the correct answer is: explanation review you answered: questions answered 11 time elapsed 00 17 08 hr min sec challenge stage 2 of 3 get 5 of 6 correct