What aspect of circadian rhythms might explain why we tend to feel so tired at night?

5. what would happen if citizens did not meet their duties and responsibilities? how would u.s. society change? explain your response.

Which of the following was a key accomplishment of the people of songhai? a. they had a strong military and became the largest empire in west africa. b. they established a center of islamic scholarship. c. they worked with iron and prospered from the gold-salt trade. d. they dominated in the trade of ivory, enslaved people, and animal skins.

Why is the netherlands vulnerable to changes in climate? a. the netherlands is against nuclear power. b. forests in the netherlands have been destroyed by acid rain. c. the netherlands wrote the kyoto protocols. d. the netherlands is low-lying country, and rising sea levels may cause flooding.