Which is an example of how the peripheral nervous system the body maintain its internal environment? muscles produce keratin so that hair can grow stronger. sweat glands break down the food that is consumed. muscles contract rapidly to produce heat on a cold day. the brain recalls information to take a test.

How many trophic levels are there in the following food chain? phytoplankton - shrimp - perch - pike - osprey

The intervention of extraterrestrials has been used to explain the bermuda triangle, a region of the atlantic ocean where ships and planes are frequently lost, leaving no evidence behind. how would this explanation best be characterized?

1. emigration the movement of people from one place to another 2. immigration a situation in which resources are being used up at a faster rate than they can be replenished 3. migration the leaving of one's homeland to settle in a new place 4. overpopulation the movement of people to a new country 5. sustainable development a situation in which the birth rate is not sufficient to replace the existing population 6. underpopulation the ability to meet current needs without reducing the ability to meet future needs 7. unsustainable development the increase in the population of a city 8. urbanization a situation in which the number of people exceeds the available natural resources in an area