Due to food scarcity in ancient times, people had to spend a.)a great deal more time than today to cultivate and find food b.)a small amount of time to cultivate and find food c.)the same amount of time as today to cultivate and find food d.)less time than needed today to cultivate and find food

answer: option (a) is the correct answer.

explanation:

the measurement of hydrogen ions in a solution is known as ph.

if ph of a solution is less than 7 then the solution is acidic. if ph of a solution is greater than 7 then the solution is basic.

when the ph of a solution equals 7, then the solution is considered as neutral.

the ph of pure water is 7, therefore, it means that concentration of hydronium ions equals that of hydroxide ions.