[this seemed so anomalous that we were almost ready to doubt our own measurements, when a simple test was suggested.]
what context clues give you the idea that anomalous is defined as: different from what is normal or expected?
a] ready to doubt
b] own measurements
c] simple test
d] was suggested

c. a group of tribes that formed a confederacy

i believe the answer is: b. mr. head had a long, tube-like face with a rounded open jaw and a short depressed nose.

this is because in the un-revised sentence it said that mr. heads face was long and tube-like, and he had a rounded open jaw. this is not a very grammatically correct because of how it seems to drag on with the and, replaced with, with, makes it sound more fluent in the description.