Answer the following question given this paragraph: The theory of evolution by natural selection explains how populations of organisms can change over time. As environments change, so must the traits of organisms if they are to survive in the new conditions. Evolution by natural selection explains how this happens. It also explains why there are so many different species of organisms on Earth today. You can see examples of the incredible diversity of living animals in Figure below . You can read more about the theory of evolution in the chapter Evolution. Q: Which theory explains how populations of organisms can change over time? Choices: - free by natural selection - changes by natural selection - intelligent selection - evolution by natural selection A:
evolution by natural selection
(Question)
Answer the following question given this paragraph: Bears get their energy from their food. Brown bears eat a varied diet, from nuts and berries to fish and other animals. When bears eat a berry, they are obtaining energy that the plant originally captured from the sun. Even when a bear eats another animal, the energy in that animal ultimately came from eating a producer that captured the sun's energy. Q: Which is the ultimate energy source in a bear's food chain? Choices: - decomposers - plants - heat - sun A:
(Answer)
sun
Ques: Answer the following question given this paragraph: What is the source of glucose for living things? It is made by plants and certain other organisms. The process in which glucose is made using energy in light is photosynthesis . This process requires carbon dioxide and water. It produces oxygen in addition to glucose. Q: What is the process in which glucose is made using energy in light called? Choices: - glucosynthesis - photogenesis - gluconeogenesis - photosynthesis A:
Ans: photosynthesis
(Q).
Answer the following question given this paragraph: Let's briefly review the basics of covalent bonding as they pertain to carbon. Carbon has four valence electrons, which have a 2s 2 2p 2 configuration in isolated carbon atoms. These four electrons allow carbon to form four covalent bonds, which can mean four single bonds or some combination of single, double, and triple bonds. Q: How many valence electrons can be found in a carbon atom? Choices: - five - three - One - four A:
(A).
four
Ques:Answer the following question given this paragraph: Potential energy is energy that is stored in a person or object. Q: Energy that is stored in a person or object is called? Choices: - vertical energy - mechanical energy - kinetic energy - potential energy A:

Ans:potential energy
Ques: Answer the following question given this paragraph: During a massive eruption, all of the material may be ejected from a magma changer. Without support, the mountain above the empty chamber may collapse. This produces a huge caldera . Calderas are generally round, bowl-shaped formations ( Figure below ). Q: Huge calderas form when the mountain above an empty chamber of what collapses? Choices: - gas - mercury - coal - magma A:
Ans:
magma