Answer the following question given this paragraph: Another sign of a species' state of health is the density of its populations. Population density is the average number of individuals in a population for a given area. Density is a measure of how crowded or spread out the individuals in a population are on average. For example, a population of 100 deer that live in an area of 10 square kilometers has a population density of 10 deer per square kilometer. Q: What is the term for the average number of individuals in a population for a given area? A:
OPTIONS:
- result density
- population structure
- Area Density
- population density

Answer: population density

Answer the following question given this paragraph: As shown in Figure above , each state of matter looks quite different at the molecular level. In the case of liquids and solids, the distances between particles are negligible relative to the size of each particle; they are essentially in direct contact with one another. In liquids, particles are free to move and exchange neighbors, resulting in the properties of a fluid. In solids, they are rigidly fixed in space and held tightly to neighboring particles. Q: In what state of matter are particles rigidly fixed in space and held tightly to neighboring particles? A:
OPTIONS:
- Gases
- liquids
- energies
- solids

Answer: solids

Answer the following question given this paragraph: Q: Exchange occurs directly with the external environment in what type of organisms? A:
OPTIONS:
- hematopoietic organisms
- cell clusters
- multicellular organisms
- unicellular organisms

Answer:
unicellular organisms