In ISO 17025; "laboratory activities" are one of three types of work taking place in a laboratory, i.e. either testing, calibration or sampling, (when the sample is going to be tested or calibrated). That means that the range of lab activities is the testing, calibration or sampling that is to be, or is accredited. Laboratories must define and document (i.e. decide and put in writing) a list of what testing, calibration or sampling activities conform to ISO 17025, as this will be listed on the accreditation certificate; and is what can be claimed as accredited.
I will give you two testing laboratory examples:
Heavy Metals (ICP-MS) in Water for Arsenic, Cadmium, Lead, Mercury
Fat in Animal Feed, Cereal Foods, Cocoa products, Dairy products.
Laboratories must perform the work themselves on an ongoing basis, and not “contract out” such work unless under controlled temporary arrangements due to an emergency.