When did muhhamad began to teach people about islam?

around 610 ce(40 years old)

he started meeting the angel jibreel and started preaching secretly to family and friends 613 was when he went publicly in his tribe

however when he started preaching completely publicly like in cities and far away tribes was in 622

answer; /// the correct answer is evidence of the olmec civilization has been found in southern american in a hot steamy forest, archaeologists have found earthen artifacts at several sites that were evidence of the olmec civilization. these   artifacts were mounds,courtyards and pyramids build of stones, also on top of the mounds were many monuments made of stone, some of these stone structures are very large, they weigh as much as 44