Where was the fertile crescent, and why was it important to the rise of civilization?

What are the 6 principles of design

Need some ! asap i need to figure out 3 major changes in bridges over time and why these changes to adapt to both improvements in technology and changing social links would also alot.

Identify the expression 8 + 8 + 8 + 8 as a numerical expression or a variable expression. for a variable expression, name the variable.