In the following questions each sentence is divided into four parts. Read each sentence to find out if there is any error in it. The error, if any, will be in one part of the sentence. The number of that part is the answer if there is no error, mark (e) as your answer. Science really begins when general principles (1)/ has to be put to the test of fact (2)/ and when practical problems and theoretical relations (3)/ of relevant factors are used to manipulate reality in human action (4)/ No error (5)