Skills in the study of biology practice questions.

Which sampling method is most appropriate for estimating the abundance of a sessile organism, such as barnacles on a rocky shore?

• Quadrat sampling
• Mark and recapture
• Collecting them with a pooter
• Following a single line transect

Answer: Quadrat sampling

Quadrats give a repeatable count of density for organisms that do not move; mark-recapture is for mobile animals and a single transect only samples one line, not overall abundance.

What is a key advantage of using a data logger with a dissolved-oxygen probe instead of taking manual readings?

• It proves that the hypothesis being tested is correct
• It removes every source of random error from the data
• It records readings automatically over a set time
• It measures the dependent variable without any probe

Answer: It records readings automatically over a set time

A data logger's benefit is automatic, frequent recording over time, which captures rapid changes and reduces observer error; it cannot prove a hypothesis or remove all error.

Which is the number 0.00062 written correctly in standard form (scientific notation)?

• 6.2 × 10⁻³
• 6.2 × 10⁻⁴
• 6.2 × 10³
• 6.2 × 10⁻⁵

Answer: 6.2 × 10⁻⁴

Standard form is a number between 1 and 10 multiplied by a power of ten; 0.00062 = 6.2 × 10⁻⁴ because the decimal point moves four places to the right.

Which of these is the best example of a testable hypothesis?

• More light will increase the rate of photosynthesis
• Plants are interesting to study in the laboratory
• Sunlight is important for all living organisms
• Photosynthesis is a complex process occurring in green leaves

Answer: More light will increase the rate of photosynthesis

A testable hypothesis makes a clear, measurable prediction linking an independent and a dependent variable; the other statements cannot be tested by measurement.

Which is an essential ethical requirement when carrying out an investigation involving human participants?

• Ensuring the results support the hypothesis
• Testing on as many people as possible
• Obtaining their informed consent first
• Keeping the aim of the study secret from them

Answer: Obtaining their informed consent first

Participants must give informed consent, understanding the study and agreeing freely; the other options are either poor practice or unethical deception.

A study finds a strong positive correlation between ice-cream sales and cases of sunburn. What is the most likely explanation for this correlation?

• Eating ice cream directly causes sunburn
• Buying ice cream prevents people from burning
• A third factor, hot weather, affects both
• There is no real relationship between them

Answer: A third factor, hot weather, affects both

Correlation does not prove causation; here both variables rise in hot weather, a confounding third factor, rather than one causing the other.