Length liquid volume and mass
It would be harder for us to identify all the different types of animals that lived long ago.
I believe the answer is D. The NASA mission which sent a probe to collide with a comet's nucleus is the Deep Impact. It is the first mission sent in order to see the interior of a comet. The comet that was aimed was called the Comet Tempel 1.
Answer D I believe! Have a nice day
