How many ways can you alter the UUU codon but keep the amino acid the same?

What does it mean for a cell membrane to be selectively permable

Enzymes are proteins that speed up reactions by providing an additional energy source supplying additional molecules for the reaction removing inhibitors that slow down reactions lowering the amount of energy required

Dna and rna share a number of similarities,but they also differ in certain aspects of their structure. wich nitrogenous base is found in rna but is not found in dna