Is there significance to the fact that human existence is the only truly sentient species within our observable universe? and if so, is there a reason to debate on it / ponder on the though? or would that be wasting time in your brain because the knowledge has no applicable use besides knowing it?

To develop a molecular clock, you need to find which of the following?

a sequence of molecules

the rate at which changes occur in a type of molecule

how much total change has occurred in a type of molecule from two different species

how many molecules a species has

Explanation:

To develop a molecular clock, you need to find which of the following?

a sequence of molecules

the rate at which changes occur in a type of molecule

how much total change has occurred in a type of molecule from two different species

how many molecules a species has

we need an attachment to see what you are talking about.