CRV vs Civic & MPG? How about AWD Civic?

I was curious if the CRV is Civic based, why is the MPG so much lower in a
CRV? Isn't the drivetrain the same with just a rear shaft coming out of the
transaxle or do they weigh a lot more?

Will Honda produce an AWD Civic and still get high MPG?
Rocky

 

Even though it is on the same chassis as the Civic, the CR-V has
considerably more weight. That is a big factor in gas mileage.

 

It also has a lot more wind resistance and, to the extent that it
actually engages the 4WD, that adds some drag as well.

 

Honda does have a version of an AWD Civic in Japan I believe. The way
its AWD operates is similar to the Suzuki Aerio's AWD system. Upon
detection of wheel slippage, the AWD system is activated and the rear
wheels begin to have power transferred to them until the vehicle is no
longer slipping. This system has been around for a few years now and
have no idea if Honda will ever port such a system for US consumers.

 

How is MPG compared to regular civic?