Read the text and answer question.
Behind a Shopping Center in New Jersey, Signs of a Mass Extinction
Behind a Lowe’s home improvement store here, scientists
are methodically scraping and sifting through ___ quarry pit
that may contain unique insights to the mass extinction that
eliminated _____ dinosaurs.
[5] Back then, about 66 million years ago, _____ oceans
were higher, and this part of southern New Jersey was a
shallow sea, 10 to 15 miles offshore from ____ ancient
mountain range that rose from the water. Today’s quarry pit
was once the sea bottom, and one particular layer about 40
[10] feet beneath the surface contains a bounty of fossils.
Kenneth J. Lacovara, a professor of paleontology and
geology at nearby Rowan University, calls the layer ___
“mass death assemblage.” He believes it may be ____ only
known collection of animal remains that dates from the mass
[15] extinction itself.
Taken from www.nytimes.com - Accessed on 06/01/2016.
The pronoun it (line 13), underlined in the text, refers to