You are likely to be involved in one or more phases when working with big data in a hadoop environment. The answer to helps the interviewer understand what kind of tools you are familiar with.If you answer that your focus was mainly on data ingestion then they can expect you to be well-versed with Sqoop and Flume, if you answer that you were involved in data analysis and data transformation then it gives the interviewer an impression that you have expertise in using Pig and Hive.