Hi Jospeh, "Contribution" is countable in your example and uncountable in the example Anatoliy mentioned. In the example you mentioned: 'who made an outstanding contribution to the progress of mankind.' here it is singular for using "an" ,however it could be written in the plural: 'who made outstanding contributions to the progress of mankind'. The difference is that the first sentence refers to the help those scientists gave altogether collectively while the second counts their efforts separately. As a substitute for "nurture" in this context you could possibly use: "Cambridge helped developing great scientists" "Cambridge brought up great scientists"

Contribution can be how countable so and uncountable. For examle: The school sees its job as preparing students to make a contribution to society. - countable All the money has been raised by voluntary contribution - uncountable When you give money, time, help etc