Question

1. all material in the universe that has mass and occupies space is called

a. covalent.
b. compound.
c. matter.
d. carbon.

1. which type of macromolecule is composed of carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur, and can produce tissues, act as hormones, and serve as enzymes?

a. proteins
b. lipids
c. nucleic acids
d. carbohydrates

1. the thin layer of rock that forms earths outer skin both on dry land and in the ocean is called earths

a. core.
b. crust.
c. mantle.
d. asthenosphere.

1. water which returns from the atmosphere to earths surface as rain or snow is called

a. evaporation.
b. transpiration.
c. condensation.
d. precipitation.

1. nutrients circulate endlessly throughout the environment in complex cycles called

a. eutrophication cycles.
b. respiration cycles.
c. photosynthesis cycles.
d. biogeochemical cycles.

1. in extreme cases, eutrophication can lead to extremely low levels of oxygen in a body of water decomposers break down all the dead producers, a condition called

a. hypoxia.
b. nitrogen fixation.
c. respiration.
d. photosynthesis.

1. ultimately, where do economies get their resources and put their wastes?

a. factories
b. cities
c. households
d. ecosystems

Explanation:

• Question 7: Matter is defined as anything that has mass and occupies space. A covalent bond is a type of chemical bond, a compound is a substance formed from two or more elements, and carbon is an element.
• Question 8: Proteins are macromolecules composed of carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur. They can produce tissues, act as hormones, and serve as enzymes. Lipids are mainly composed of carbon, hydrogen, and oxygen and are used for energy storage. Nucleic acids (like DNA and RNA) are composed of carbon, hydrogen, oxygen, nitrogen, and phosphorus. Carbohydrates are composed of carbon, hydrogen, and oxygen and are used for energy.
• Question 9: The crust is the thin outer layer of the Earth. The core is the innermost layer, the mantle is between the core and the crust, and the asthenosphere is a part of the upper mantle.
• Question 10: Precipitation is water that returns from the atmosphere to the Earth's surface as rain or snow. Evaporation is the process of water turning into vapor. Transpiration is the release of water vapor from plants. Condensation is the process of water vapor turning into liquid.
• Question 11: Biogeochemical cycles are the cycles in which nutrients circulate through the environment. Eutrophication cycles are related to the over - enrichment of nutrients in water. Respiration cycles are part of how organisms obtain energy. Photosynthesis cycles are part of how plants produce food.
• Question 12: Hypoxia is a condition of extremely low oxygen levels. Nitrogen fixation is the process of converting nitrogen gas into a usable form. Respiration is the process of obtaining energy. Photosynthesis is the process of producing food in plants.
• Question 13: Ecosystems provide resources (like raw materials, food) and absorb wastes (through processes like decomposition). Factories, cities, and households are parts of the economy but ultimately rely on ecosystems for resources and waste disposal.

Answer:

1. c. matter
2. a. proteins
3. b. crust
4. d. precipitation
5. d. biogeochemical cycles
6. a. hypoxia
7. d. ecosystems