Final answer:
The biologist is collecting longitudinal data, which tracks changes over time within a subject or subjects, as opposed to cross-sectional data that compares different subjects at a single point in time.
Step-by-step explanation:
The biologist collecting and examining 150 frogs to study a species is gathering c) Longitudinal data. This type of data involves following a subject or subjects over an extended period of time to observe changes and developments. This is often contrasted with cross-sectional data, which looks at multiple subjects at a single point in time. In biology, longitudinal studies can be very informative for understanding growth patterns, behavior changes, and the effects of environmental changes on organisms.
Other types of data discussed include qualitative data, which describes qualities or characteristics that are not necessarily numerical, and quantitative data, which can either be discrete (countable) or continuous (measurable and can take on any value within a range). For instance, a researcher interviewing prisoners collects both quantitative data (demographics) and qualitative data (reasons for taking educational opportunities).
The term descriptive data could also apply, depending on whether the data collected is used to describe the population of frogs.