Can someone explain how u are supposed to do this and get the answered

Apiece of metal with a length of 1.42 cm was measured using four different instruments. which of the following measurements is the most accurate?

How many moles of oxygen gas are produced from the decomposition of six moles of potassium chlorate

Which is a characteristic of the electron sea model for metallic bonding? molecular orbitals overlap to produce bands. electrons flow easily between metal nuclei. electrons are in fixed positions in the orbitals. atomic nuclei are arranged in an irregular pattern.