What does mensuration indicate in early music notation?

a: rhythm
b: pitch
c: key signature
d: time signature

i think it's either a or b

The answer is A. Rhythm. 

Mensural notation is the musical notation system used for European vocal polyphonic music from the later part of the 13th century until about 1600. The term "mensural" refers to the ability of this system to describe precisely measured rhythmic durations in terms of numerical proportions between note values.

Where’s the

Photography has changed its subject matter quite a lot over the past few years. in the 1800's, it was considered normal for families to have  post mortem photos of their loved ones, and now that would be completely unacceptable. i think that photographers have always pushed boundaries and have been eager to capture everything, it is just society that changes their boundaries.