The arrangement of microtubules in cilia and flagella follows which pattern?
1. 9+0 arrangement - 9 singlet microtubules arranged peripherally
2. 9+2 arrangement - 9 doublet microtubules peripherally and 2 central singlets
3. 9+2 arrangement - 9 triplet microtubules peripherally and 2 central doublets
4. 8+2 arrangement - 8 doublet microtubules peripherally and 2 central singlets