Compared to North Africa, West Africa is 1. an area with a much higher standard of living

2. more culturally diverse with dozens of ethnic groups

3. far less densely populated

4. more likely to be Islamic

What is the speed of sound in water

One of the brightest comets of the 20th century was comet hyakutake, which passed close to the sun in early 1996. the orbital period of this comet is estimated to be about 30,000 years. find the semi-major axis of this comet’s orbit. compare it to the average sun-pluto distance and to the distance to alpha centauri, the nearest star to the sun, which is 4.3 light-years distant.

Which of the following is a way that advancements in technology improve humans' ability to measure air quality and protect human health?