Question

review vocabulary
choose the letter of the best answer.

1. a possible explanation for a set of observations that must be tested is called a

□a. theory.
□b. law.
□c. fact.
□d. hypothesis.

1. a well - tested explanation for a broad range of natural events is called a

□a. theory.
□b. law.
□c. fact.
□d. hypothesis.
match the vocabulary term to its definition.

1. in an experiment, its variables are changed.

a. bias

1. all of the chemical reactions that an organism carries out to stay alive.

b. control group

1. a personal preference that is not scientific.

c. metabolism
review key questions
provide evidence and details to support your answers.

1. a scientist grows tomatoes in greenhouses that differ only in the amount of carbon dioxide in the air. he determines the weight of tomatoes produced by plants in each greenhouse, and compares them to each other and to tomatoes grown in air with a natural, unaltered amount of carbon dioxide. is this a controlled experiment? why or why not?
2. a group of scientists decide to post their research results on the internet instead of publishing in a scientific journal. what part of the scientific process have they skipped and why does it matter?
3. why is a virus not considered a living organism?

Explanation:

1. A hypothesis is a possible explanation for a set of observations that must be tested. A theory is well - tested, a law is a description of a natural phenomenon, and a fact is something that is known to be true.
2. A theory is a well - tested explanation for a broad range of natural events.
3. In an experiment, the experimental group has its variables changed.
4. Metabolism is all of the chemical reactions that an organism carries out to stay alive.
5. Bias is a personal preference that is not scientific.
6. This is a controlled experiment because there is a control group (tomatoes grown in air with a natural amount of carbon dioxide) and only one variable is changed (the amount of carbon dioxide in the greenhouses).
7. They have skipped peer - review. Peer - review is important as it ensures the quality, validity, and reliability of research by having other experts in the field evaluate the work.
8. A virus is not considered a living organism because it cannot reproduce on its own, lacks cells, and does not carry out metabolic processes without a host cell.

Answer:

1. D. hypothesis
2. A. theory
3. Experimental group (not in options, but the concept answer)
4. c. metabolism
5. a. bias
6. Yes, because there is a control group and only one variable is changed.
7. They skipped peer - review. It matters because it ensures research quality and reliability.
8. Because it cannot reproduce on its own, lacks cells, and does not carry out metabolic processes without a host cell.