Chapter 1 Review Questions

1. An inference is

The same as an observation

A logical interpretation of an observation

A statement involving numbers

The best way to avoid bias

An inference is a logical interpretation of an observation. When we make an observation, we gather information through our senses. However, an inference goes beyond the observation and involves using reasoning and logic to draw conclusions or make interpretations based on the available evidence. It involves connecting the dots and making sense of the observed information. Inferences are important in fields such as science, where scientists make logical interpretations based on their observations to develop theories and explanations for phenomena.

Explanation

An inference is a logical interpretation of an observation. When we make an observation, we gather information through our senses. However, an inference goes beyond the observation and involves using reasoning and logic to draw conclusions or make interpretations based on the available evidence. It involves connecting the dots and making sense of the observed information. Inferences are important in fields such as science, where scientists make logical interpretations based on their observations to develop theories and explanations for phenomena.

2. To be useful in science, a hypothesis must be

Measurable

Observable

Testable

Correct

Only testable hypotheses are useful in science. Even incorrect hypotheses can give useful information about how the natural world works. Not all experiments involve things you can measure or directly see, but all must have a testable hypothesis.

Explanation

Only testable hypotheses are useful in science. Even incorrect hypotheses can give useful information about how the natural world works. Not all experiments involve things you can measure or directly see, but all must have a testable hypothesis.

3. Which statement about a controlled experiment is true?

All the variables must be kept the same.

Only one variable is changed at a time.

Scientists always use controlled experiments.

Controlled experiments cannot be performed on living things.

Answer B is the definition of a controlled experiment. Not all studies lend themselves to controlled experiments. For example, field observations are, by definition, not controlled experiments.

Explanation

Answer B is the definition of a controlled experiment. Not all studies lend themselves to controlled experiments. For example, field observations are, by definition, not controlled experiments.

4. Which statement is not an observation?

The insect has three legs on the left side.

The insect has a pattern on its back.

The insect's pattern shows that it is poisonous.

The insect is green, white, and black.

The statement "The insect's pattern shows that it is poisonous" is not an observation because it involves an interpretation or inference about the insect's pattern rather than a direct observation of the pattern itself. Observations are typically factual and objective descriptions of what is directly observable, while interpretations involve making conclusions or judgments based on those observations.

Explanation

The statement "The insect's pattern shows that it is poisonous" is not an observation because it involves an interpretation or inference about the insect's pattern rather than a direct observation of the pattern itself. Observations are typically factual and objective descriptions of what is directly observable, while interpretations involve making conclusions or judgments based on those observations.

5. The statement "The worm is 2 cm long" is a(n)

Quantitative observation

Qualitative observation

Inference

Hypothesis

The statement "The worm is 2 cm long" is a quantitative observation because it provides a specific measurement of the length of the worm. It is a factual statement based on direct measurement or observation, rather than an interpretation or assumption.

Explanation

The statement "The worm is 2 cm long" is a quantitative observation because it provides a specific measurement of the length of the worm. It is a factual statement based on direct measurement or observation, rather than an interpretation or assumption.

6. A scientific theory is

Another word for hypothesis

A well tested explanation that unifies a broad range of observations

The same as a conclusion of an experiment

Established when the conclusion of two separate experiments are the same

A scientific theory is a well tested explanation that unifies a broad range of observations. This means that a scientific theory is not just a guess or hypothesis, but it is based on extensive research and experimentation. It is a comprehensive explanation that can account for a wide variety of observations and has been repeatedly tested and supported by evidence. A scientific theory goes beyond the conclusion of a single experiment and provides a framework to understand and predict natural phenomena.

Explanation

A scientific theory is a well tested explanation that unifies a broad range of observations. This means that a scientific theory is not just a guess or hypothesis, but it is based on extensive research and experimentation. It is a comprehensive explanation that can account for a wide variety of observations and has been repeatedly tested and supported by evidence. A scientific theory goes beyond the conclusion of a single experiment and provides a framework to understand and predict natural phenomena.

7. Which process is used by organisms to keep their internal conditions relatively stable?

Metabolism

Reproduction

Evolution

Homeostasis

Homeostasis is the process used by organisms to maintain a relatively stable internal environment. It involves various physiological mechanisms that regulate temperature, pH levels, water balance, and other factors to ensure optimal conditions for the body's cells. Homeostasis is crucial for the proper functioning of an organism and allows it to adapt to changes in the external environment while keeping internal conditions within a narrow range. Metabolism, reproduction, and evolution are important processes in organisms but do not specifically refer to the maintenance of internal stability.

Explanation

Homeostasis is the process used by organisms to maintain a relatively stable internal environment. It involves various physiological mechanisms that regulate temperature, pH levels, water balance, and other factors to ensure optimal conditions for the body's cells. Homeostasis is crucial for the proper functioning of an organism and allows it to adapt to changes in the external environment while keeping internal conditions within a narrow range. Metabolism, reproduction, and evolution are important processes in organisms but do not specifically refer to the maintenance of internal stability.

8. Please refer to the graph on page 32 of the course text book to answer this question. Which is a scientific inference based on the contents of the graph?

The flies in population B were healthier than those in population A.

A fly population with more available space will grow larger than one with less space.

In 40 more days, the sizes of both populations would decrease at the same rate.

The pattern shown in this graph is true only for fruit flies.

B is the only answer that can be inferred based solely on the graph.

Explanation

B is the only answer that can be inferred based solely on the graph.