How many electrons are in the outer energy levels of the highlighted group of elements

According to the loco mass the mass of reactants and products

Which best explains why there are 64 possible codons in the genetic code and only 20 amino acids that make protiens of living organisms on earth

Out of the seven main animal groups (fish, mammals, birds, insects, reptiles, amphibians, and arachnids), how many contain members with internal backbones? a. 5 b. 3 c. 7 d. 1