During dna replication in a human cell, 6 billion bases must be paired properly. which characteristic of dna best allows for high levels of accuracy during this process?

DNA polymerase III has a subunit for proofreading during DNA replication. As replication continues and the polymerase III enzyme detects a mismatched base pair, through a deformity in the double helix structure, the polymerase backs up, nicks the mismatched base and replaces it with the correct base before continuing replication.   

the correct answer in apex is tissue development, i know because i just had this question

answer: ice crystals in air

the water from the water body or another source of water gets evaporated as water vapor as an effect of heat on water. these water vapor rises in the upper layers of the earth atmosphere under high atmospheric pressure. the atmospheric pressure of these water molecules starts to decrease due to the effect of cold air. the invisible water vapor condenses into visible water droplets and ice crystals.these ice crystals and water droplets being less denser than the surrounding air floats on air as clouds.