The skin is the first line of defense in preventing penetration by infectious agents. however, the skin can be bypassed. which of the following scenarios allows an infectious agent to enter the body without damaging the skin? a. a person is infected with malaria when a mosquito bite punctures his skin. b. a girl gets a staph infection when she falls and scrapes her knee. c. a boy is infected with rabies when a dog bites his leg. d. bacteria on food is ingested through the mouth.

Coral reefs support more species per unit area than any other marine environment on earth. what is one way coral reefs are important to the health of the biosphere

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

About how many years does it take for one cycle of surface water to become deep water and then surface water again in the oceans? 101001,000