Why did southern plantation owners need slaves for labor

mainly cotton

Explanation:

cotton had many thorns, so no one wanted to do the work. when slaves came along, it was an advantage. they used it for other puposes too, like gathering other  crops, or planting them, or tending to them, butit was cotton that was the main thing.

the effect of the ming leaders banning ships with more than two masts was that there was no further construction of ships masts, because there was a surplus. ming emperors disallowed foreign exploration

one central belief of buddhism is often referred to as reincarnation -- the concept that people are reborn after dying. buddhism is a philosophy of life expounded by gautama buddha ("buddha" means "enlightened one"), who lived and taught in northern india in the 6th century b.c.