Click on this useful link for AL Economics Students relating to injections and withdrawals of income and see where to find the relevant section within the spec below:-
Edexcel spec reference 2.4.2 a) The impact of injections into, and withdrawals from, the circular flow of income.
AQA spec reference The effect of changes in injections and withdrawals on national income.
OCR spec reference P 19 Explain what is meant by injections and leakages within the circular flow