The nuclear pore complex (NPC) contains structures that form a gel-like matrix that allow small molecules to diffuse through, but require larger proteins to enter via importin or other nuclear chaperones.

Measurement is inevitable because in every single thing we do we measure.for instance, if you are a family of four,the food prepared will be less than the food prepared for a family of about 15 people.this is measurement.if not so,the food prepared will go waste.again, the drugs prescribed by the doctor is measured to avoid over dose or under dose of medication.this can be harmful to ones health