Answer:
It has a negative effect on the farming economy in Africa.
Explanation:
I may think that Europe has certainly done Africa few favors and West Africa in particular. Colonization made an immediate and long standing impact on all parts of Africa. West Africa was particularly affected by the slave trade. The areas on the coast that took slaves and sold them to Europeans became richer.
The type of wave which needs a medium to travel are sound waves because they travel by oscillating electromagnetic fields
<h3>What is a Sound Wave?</h3>
This refers to the waves of refraction which is propagated by a plastic medium.
With this in mind, we can see that mechanical waves are the types of wave that needs a medium for propagation and a sound wave is an example of a mechanical wave because it travels by oscillating electromagnetic fields.
Read more about mechanical waves here:
brainly.com/question/9242091
Ancient China was built along the two main rivers—first the Yellow River (Huang He) in the north, and later the Yangtze in the south. In the settlements along the Yellow River, people grew millet in the rich, easily worked loess soil. In the south, people grew rice along the Yangtze river, ate a good deal of fish, together with vegetables, especially water plants such as water chestnuts and lotus. Along with dogs, pigs and cattle, people in the south had water buffalos to help work the soil. By the heavy use of human labor, the same area of land in the south could grow about twice as much food as in the north.
the first one is b and the second one is a
