*Question*
Answer the following question given this paragraph: in animals but also in plants. An organ system is a higher level of organization that consists of functionally related organs. Mammals have many organ systems. For instance, the circulatory system transports blood through the body and to and from the lungs; it includes organs such as the heart and blood vessels. Organisms are individual living entities. For example, each tree in a forest is an organism. Single-celled prokaryotes and single-celled eukaryotes are also considered organisms and are typically referred to as microorganisms. All the individuals of a species living within a specific area are collectively called a population. For example, a forest may include many pine trees. All of these pine trees represent the population of pine trees in this forest. Different populations may live in the same specific area. For example, the forest with the pine trees includes populations of flowering plants and also insects and microbial populations. A community is the sum of populations inhabiting a particular area. For instance, all of the trees, flowers, insects, and other populations in a forest form the forest's community. The forest itself is an ecosystem. An ecosystem consists of all the living things in a particular area together with the abiotic, non-living parts of that environment such as nitrogen in the soil or rain water. At the highest level of organization (Figure 1.16), the biosphere is the collection of all ecosystems, and it represents the zones of life on earth. It includes land, water, and even the atmosphere to a certain extent. Q: What organ system transports blood through the body and to and from the lungs? Choices: - metabolism - digestive - nervous - circulatory A:
**Answer**
circulatory

*Question*
Answer the following question given this paragraph: Sometimes air doesn't mix in the troposphere. This happens when air is cooler close to the ground than it is above. The cool air is dense, so it stays near the ground. This is called a temperature inversion ( Figure below ). An inversion can trap air pollution near the surface. Temperature inversions are more common in the winter. Can you explain why?. Q: In what season are temperature inversions more common? Choices: - spring - autumn - summer - winter A:
**Answer**
winter

*Question*
Answer the following question given this paragraph: Corrosion is a galvanic process that can be prevented using cathodic protection. CONCEPTUAL PROBLEMS 1. Q: What is a galvanic process that can be prevented using cathodic protection? Choices: - explosion - sublimation - vaporization - corrosion A:
**Answer**
corrosion

*Question*
Answer the following question given this paragraph: A mutation is a change in the base sequence of DNA or RNA. Environmental causes of mutations are called mutagens. The effects of a mutation depend on the type of mutation and whether it occurs in a gamete or body cell. Q: What is the term for environmental causes of mutations? Choices: - pollutants - catalysts - carcinogens - mutagens A:
**Answer**
mutagens