Question

which sample would be appropriate for dating by means of radioactive carbon?
a mastodon that is about 15,000 years old
an igneous intrusion from a 250 - million - year - old volcano eruption
a homo erectus skeleton thought to be around 800,000 years old
stromatolites containing 3 - billion - year - old bacterial mats
the sediments of the cretaceous sea where they are now exposed on land

Explanation:

Radioactive carbon - dating (carbon - 14 dating) is effective for dating organic materials that are less than about 50,000 - 60,000 years old. A mastodon is an organic material and its age (15,000 years) is within the effective range of carbon - 14 dating. Igneous intrusions, very old fossils like Homo erectus (800,000 years), 3 - billion - year - old stromatolites, and Cretaceous sea sediments are either inorganic or too old for carbon - 14 dating.

Answer:

A. A mastodon that is about 15,000 years old