In case of hcp structure, how are spheres in first, second and third layers arranged?

Sites of first, second and third moulting of Ascaris larva are

Sites of first, second and third moulting of Ascaris larva are

Sites of first, second and third moulting of Ascaris larva are

The first elements of first, second and third transition series respectively are

In a hexagonal close packed (hcp) structure of spheres, the fraction of the volume occupied by the sphere is A. In a cubic close packed structure the fraction is B. The relation for A and B is:

Which of the following statements are correct - 1. CCP structure has three different type of layers. 2. In CCP structure, first and fourth layers are repeated. 3. In an HCP structure, first and fourth layers are repeated. 4. In FCC packing, the neighboring face centered atoms touch each other.