Context: Time is one of the seven fundamental physical quantities in both the International System of Units and International System of Quantities. Time is used to define other quantities—such as velocity—so defining time in terms of such quantities would result in circularity of definition. An operational definition of time, wherein one says that observing a certain number of repetitions of one or another standard cyclical event (such as the passage of a free-swinging pendulum) constitutes one standard unit such as the second, is highly useful in the conduct of both advanced experiments and everyday affairs of life. The operational definition leaves aside the question whether there is something called time, apart from the counting activity just mentioned, that flows and that can be measured. Investigations of a single continuum called spacetime bring questions about space into questions about time, questions that have their roots in the works of early students of natural philosophy.

Question: Time is one of how many fundamental physical quantities?
Answer: seven

Question: Time is one of the fundamental physical quantities in which two systems?
Answer: the International System of Units and International System of Quantities

Question: What is an example of a quantity that time is used to define, mentioned in the paragraph?
Answer: velocity

Question: Investigations of what brought questions of space into questions about time?
Answer: a single continuum called spacetime

Question: Philosophy is one of how many fundamental physical quantities?
Answer: Unanswerable

Question: In what two systems is philosophy considered a fundamental physical quantity?
Answer: Unanswerable

Question: What is something else that philosophy is used to define?
Answer: Unanswerable

Question: What kind of experiments can be used when understanding philosophy?
Answer: Unanswerable

Question: Who first used philosophy to understand everyday affairs of life?
Answer: Unanswerable

Question: Philosophy is one of how many fundamental physical quantities?
Answer: Unanswerable

Question: Philosophy is one of the fundamental physical quantities in which two systems?
Answer: Unanswerable

Question: What is an example of a quantity that philosophy is used to define, mentioned in the paragraph?
Answer: Unanswerable

Question: Investigations of what brought questions of space into questions about philosophy?
Answer: Unanswerable

Question: What do questions about velocity have their roots in?
Answer: Unanswerable