Question

in october of 2011, world population reached seven billion people. every second that number increases, but what does that number really mean? through the questioning and analysis of population data, we as global citizens can better understand how we live and interact with our world. to help with this understanding we ask for help from demographers (write in the definition):

Explanation:

Demographers study human populations, including size, structure, distribution, and changes.

Answer:

People who study human populations, their size, structure, distribution and changes.