The phylum of seedless vascular plants has about 1000 known living species, including those in the genera Lycopodium and Selaginella; the gametophyte of some of these species cannot photosynthesize, and instead uses mycorrhizae to obtain nutrients.

Give the biological term for: structures that display characteristics of living organisms only within living cells

Aflashlight battery is an example of a) potential energy b) kinetic energy c) thermal energy d) solar energy

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