Okay, I would bend over backwards! :)
Leeuwenhoek was inspecting things under his artifial magnifying instrument and found single-cell living beings that he alluded to as protists.
Water is used in many reactions in the body, both enzymatic and chemical. Water within blood and lymphatic system is responsible for the transport of hormones, antidotes oxygen and nutrients.
Metabolism can be described as entirety of chemical reactions which take place within a cell, the result of which is energy for processes which take place in the body.
Answer:
4
If the beaker was not cleaned, starch could have been in it.