Question 1

Which of the following best describes the difference between a hypothesis and a scientific theory?

Accepted Answer

A hypothesis is a testable statement based on observations, while a theory is a well-supported explanation that unifies a broad range of observations.

Question 2

In a controlled experiment testing the effect of a new drug on blood pressure, which of the following is the dependent variable?

Accepted Answer

The blood pressure measured after treatment

Question 3

Which of the following is the correct sequence of steps in the scientific method?

Accepted Answer

Observe and generalize → Formulate a hypothesis → Make a testable prediction → Experiment or observe

Question 4

A scientist observes that a certain drug lowers blood pressure in rats, cats, and dogs. She then predicts it will lower blood pressure in all mammals. What type of reasoning is she using?

Accepted Answer

Inductive reasoning

Question 5

Why is it important to use a placebo in a blind study?

Accepted Answer

To remove the power of suggestion as a variable

Question 6

Which of the following sources is considered the most credible for scientific information?

Accepted Answer

A peer-reviewed journal article

Question 7

A solution has a hydrogen ion concentration of $$10^{-7}$$ moles/liter. What is its pH?

Accepted Answer

$$7$$

Question 8

Which property of water allows it to dissolve table salt (NaCl)?

Accepted Answer

Water is a polar molecule, allowing it to surround and separate Na$$^+$$ and Cl$$^-$$ ions.

Question 9

Which of the following best explains why water is effective at regulating body temperature?

Accepted Answer

Water can absorb and hold a large amount of heat energy before changing temperature.

Question 10

If the pH of blood drops from 7.4 to 7.0, what happens to the hydrogen ion concentration?

Accepted Answer

It increases by a factor of $$2.5^{10}$ (about 2.5 times for each 0.1 pH unit)

Question 11

Which of the following is an example of a hydrophilic substance?

Accepted Answer

Table salt (NaCl)

Question 12

What is the main function of buffers in the human body?

Accepted Answer

To maintain a stable pH by accepting or donating hydrogen ions

Question 13

A news article claims a new supplement cures headaches based on one person's experience. What is the best way to evaluate this claim?

Accepted Answer

Look for peer-reviewed studies with controlled experiments

Question 14

Which of the following statements about acids and bases is correct?

Accepted Answer

Acids donate hydrogen ions, while bases accept hydrogen ions.

Question 15

Which of the following best describes the relationship between correlation and causation?

Accepted Answer

Correlation means two variables are related, but does not prove one causes the other.

Question 16

Which of the following is a real-world example of a buffer system in the human body?

Accepted Answer

The blood bicarbonate buffer system: $$\mathrm{$$HCO_3$$^-}$$ and $$\mathrm{H_2CO_3}$$

Question 17

A student designs an experiment to test the effect of sunlight on plant growth. She keeps all variables constant except the amount of sunlight each group receives. What is the independent variable?

Accepted Answer

The amount of sunlight

Question 18

Which of the following best explains why polar molecules dissolve well in water?

Accepted Answer

Polar molecules have charged regions that interact with the charged ends of water molecules.

Question 19

Which of the following is a fact rather than a conclusion?

Accepted Answer

Drug X lowers blood pressure in 85% of the control group.

Question 20

Which of the following best describes the role of water in hydrolysis reactions?

Accepted Answer

Water is used to break apart large molecules into smaller ones.

Scientific Method and Chemistry of Living Things: Study Notes for Human Biology

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