Question

1. what is the building block of all matter? a. molecules b. atoms c. cells d. elements 19. which demonstrates a physical change? a. milk becoming sour b. iron rusting c. ice melting d. bread baking 20. which best describes the relationship between population and environmental impact in the ipat equation? a. they are inversely related b. they are directly proportional c. they have no relationship d. they are randomly related 21. what is the primary source of energy in most ecosystems? a. a. decomposers b. b. the sun c. c. consumers d. d. soil nutrients 22. which of the following best describes the 10% rule in energy transfer? a. a. 10% of energy is converted to heat b. b. only 10% of energy is lost between trophic levels c. c. approximately 10% of energy transfers to the next trophic level d. d. 10% of energy returns to producers 23. in a food chain, what immediately follows primary consumers? a. producers b. secondary consumers c. tertiary consumers d. decomposers 24. what distinguishes an omnivore from other consumers? a. it only eats meat b. it only eats plants c. it eats both plants and animals d. it breaks down dead organisms 25. which process allows producers to create their own food? a. decomposition b. respiration c. consumption d. photosynthesis 26. why does an energy pyramid have a wide base and narrow top? a. there are fewer producers than consumers b. energy increases at each level c. energy decreases at each level d. decomposers are only found at the top

Explanation:

1. Atoms are the building - blocks of all matter. Molecules are made of atoms, cells are in living organisms, and elements are made of atoms.
2. Ice melting is a physical change as it only changes the state from solid to liquid without forming new substances. Milk becoming sour, iron rusting, and bread baking are chemical changes.
3. In the IPAT equation, population and environmental impact are directly proportional. More people generally mean more impact on the environment.
4. The Sun is the primary source of energy for most ecosystems. It provides energy for photosynthesis in producers.
5. The 10% rule in energy transfer states that approximately 10% of energy transfers to the next trophic level. Most energy is lost as heat.
6. In a food chain, secondary consumers immediately follow primary consumers. Primary consumers eat producers, and secondary consumers eat primary consumers.
7. An omnivore eats both plants and animals. Carnivores eat only meat, herbivores eat only plants, and decomposers break down dead organisms.
8. Producers create their own food through photosynthesis, using sunlight, carbon - dioxide, and water to make glucose and oxygen.
9. An energy pyramid has a wide base and narrow top because energy decreases at each level. There is more energy available at the producer level and less as you move up the trophic levels.

Answer:

1. B. Atoms
2. C. Ice melting
3. B. They are directly proportional
4. B. The Sun
5. C. Approximately 10% of energy transfers to the next trophic level
6. B. Secondary consumers
7. C. It eats both plants and animals
8. D. Photosynthesis
9. C. Energy decreases at each level