[otabdeveloper4]

The answer is pretty obvious - building this intricately organized matter from scratch out of sunlight and elements is extremely inefficient, much better to recycle the existing bulding blocks of lower levels of organization.

(You don't make software from scratch from sand and electricity, you use an off-the-shelf CPU and existing libraries.)

[RcouF1uZ4gsC]

Most of the meat consumed is not used to build things but is consumed by the body for energy.

[otabdeveloper4]

Protein is used by the human body as construction material, not as fuel. (It is possible to use protein as a fuel source, but virtually no modern human follows a diet where that actually happens.)

[aatd86]

What's matter?

[krallja]

Nothing, what’s matter with you?

[aatd86]

Hopefully nothing.