Is it true that many civilizations took place in the Sahara and Sahel region of Africa in the past? if yes Mention Two civilizations which left a great impact and their achievements.

Rocks that contain crystals that are roughly equal in size and can be identified with the unaided eye are said to exhibit a texture.

How many time zone are there on earth

Which statements describe sustainable development? multiple answer choice -fishing does not remove more fish from water systems than can be replaced by the number of fish that will be born to replace them. -sustainable development is development that is designed to improve the economic conditions in less-developed countries. -sustainable development is mainly a regional issue. -sustainable development means water is used at a rate that won't reduce the amount available for future use. - sustainable development policies only need to be concerned with environmental protection. - trees cannot be cut down faster than the number that will be replaced by new growth.