Which statement explains how smog forms?

a) volcanoes erupt and release ash into the sky.

b) strong storms pick up soil and mix it with fog.

c) sunlight and heat react with gases in the atmosphere.

d) gases move high into the atmosphere and then fall to earth in rain.

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

Crossing over and independent assortment are important activities that occur during meiosis. what is the significance of these activities

Which situation is an example of not doing work? lifting a couch throwing a baseball running up stairs carrying a box