Answer:
Controlled Investigation
Field Investigation
Explanation: In a controlled experiment, the scientist has total control over the environmental conditions. The temperature, humidity, amount of light, amount of noise, materials, etc. can all be controlled and monitored by the scientist throughout the investigation.
A field investigation involves observing and measuring plants and animals (including people) in their natural habitat or environment without changing, harming, or altering the setting or any part of the test subjects. Like in a controlled experiment, the scientist chooses to observe and measure how one change (IV) has a measurable effect (DV) on something else.
Community, population, ecosystem shows the levels of organizational hierarchy from least complex to most complex. The correct option among all the options that are given in the question is the third option. It is a fact that a community will always be smaller than the population, since numerous communities make up the population. Ecosystem is the largest.
