"What would railroads do if every state had different requirements for smokestacks or track width?"

The train will move on the roads.

Explanation:

If every state had different requirements for smokestacks or track width, the trains should be run on the roads because if there is different requirement for track width, it is impossible to run same type of train on these tracks. One another act will be done and that was to make different types of trains for each state so that they can move on the tracks. But it is impossible for having different track width, it must be of same width.

the statement is true

label a cell membrane

label b cytoplasm

label c ribosomes

label d dna

the membrane forms the outside of the cell

cytoplasm is the liquid within

ribosomes are the components within that distribute rna

the dna is the genetic make-up