Question

the kola superdeep borehole is in northwestern russia. it is not a single hole, but a group of holes connected underground. they were drilled into the earths crust as part of a scientific project. as a result of the drilling, researchers learned that an entire layer of the earths crust thought to exist actually did not. and deep in the earth, researchers found the remains of ancient species of single - cell ocean plants. this was unexpected. the plants were found in an area where scientists thought the crust was too hot to preserve remains. one of these holes, sg - 3, capped in 1989, is the deepest in the world. the kola superdeep borehole led to discoveries conflicts injuries regulations

Explanation:

The text mentions that as a result of drilling the Kola Superdeep Borehole, researchers learned an earth - crust layer didn't exist and found ancient single - cell ocean plant remains. These are discoveries.

Answer:

A. discoveries