Final answer:
In scientific research, 'in vivo' refers to experiments conducted inside living organisms, while 'in vitro' denotes measures conducted outside of living organisms, usually in controlled lab settings.
Step-by-step explanation:
The terms in vivo and in vitro are significant in biology and research to differentiate between types of scientific studies. The former refers to measures conducted inside living organisms, meaning any experiments or observations are made within an intact, living organism. For instance, this can include studying how a drug affects a disease within a human patient. The latter term, in vitro, translates literally to 'in glass,' and it encompasses measures conducted outside living organisms; these are typically done in controlled environments such as a petri dish or a test tube where researchers can manipulate conditions more precisely. Such experiments can consist of studying cellular responses to a drug in cultured cells.
Both in vivo and in vitro methods have their unique applications and limitations. For example, while in vitro experiments allow for high levels of control over environmental variables and can simplify complex biological processes, they may not fully replicate the interactions and physiology of a complete organism. Conversely, in vivo studies provide a more holistic view of biological processes within the natural context of an organism but can be more challenging to control and have ethical considerations.
The correct options for the given question are:
a) Measures conducted inside living organisms
b) Measures conducted outside living organisms
In vivo measures are conducted inside living organisms, while in vitro measures are conducted outside living organisms. In vivo measures involve studying biological processes or phenomena within living organisms, such as studying the effects of a drug on a person. In contrast, in vitro measures involve studying biological processes or phenomena outside living organisms, such as testing a drug on cells in a petri dish.