Omg i only need two more need help on this ​

What is the number 321,000,000 in scientific notation? also what is the number? ?

Hii1977 cleaner shrimp are a species of shrimp that clean parasites from other organisms. fish allow the shrimp to eat the parasites in their mouth. the shrimp get a source of nutrition. the relationship between the shrimp and the fish is this association indicates that for the smaill aneser arecommensal,mutualistic,or parasitic for the begger one the anser are the shrimp and fish benefit each other , the shrimp harm the fish, or the fish do not benetit from the shrimp

Each person in an it department of 25 people works on at least one of 3 major projects: system security, program implementation, platform development. 10 people work on system security, 13 work on program implementation, and 12 work on platform development. 4 people work on system security and platform development, 5 people work on program implementation and platform development, and 2 people work on all three projects. how many people work on system security and program implementation?