Sickle-cell anemia is an inherited disease that affects red blood cells. In people who have this disease, one amino acid is substituted for another amino acid in a blood protein. What causes sickle-cell anemia? 1. mutation

2. replication

3. translation

4. transcription

b

is correct hope this   also i learnd this in middle school

enzyme active site and substrate specificity

enzymes bind with chemical reactants called substrates. there may be one or more substrates for each type of enzyme, depending on the particular chemical reaction. in some reactions, a single-reactant substrate is broken down into multiple products