30) Which of these statements are true? 1 chromosome is made of DNA
2 chromosomes are found in the cell membrane
3 chromosomes are always formed from a single gene
4 genes are short sections of DNA

A) 1, 2, 3 and 4
B) 2, 3 and 4
C) 2 and 3
D) 1 and 4

the reaction mixture contains some ammonia, plus a lot of unreacted nitrogen and hydrogen. the mixture is cooled and compressed, causing the ammonia gas to condense into a liquid. the liquefied ammonia is separated and removed. the unreacted nitrogen and hydrogen are then recycled back into the reactor .