Paul Zamecnik and his colleagues carried
out an experiment to track the fate of radioactive leucine molecules attached
to tRNAs (Transport RNAs). In their experiment, they found out that amino acids
are transferred from tRNAs to proteins. Paul Zamecnik, an American scientist, played
a major role in the early history of molecular biology.
The three stages are early childhood middle childhood and adolescence
1. Cigarettes
2. Beer
3. Antacids
4. Cocaine
I said in comment but the answer is
Pyramid of Biomass
Good luck on your assignment dear ^^