20. the greeks were able to defeat the persians in war because of their a. show of unity b. superior numbers c. powerful weapons d. many allies

What major factors play a role in global warming? 1. human activity and normal climate conditions 2. natural factors and human activity 3. normal climate conditions and abnormal human activities 4. abnormal human activities and natural factors

Adesert is an example of a(n) and the gobi desert is an example of a(n) a. ecosystem biome b. biome ecosystem c. ecosystem climate d. climate biome

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.