D: All the variables are controlled except one.
Cell wall and chloroplast are two examples of structures which are found in plant cells but not in animal cells.
A.) Launch a satellite
Landing on the moon takes years to figure out. (How, when, what is the purpose, etc.) Capturing an asteroid is beyond difficult and would also take years to figure out how to do so.
Launching a space probe has yet to be done BUT we have had a satellite launched (hence how we get satellite images.)
