What is Wolff’s Law and why is it important to the design of biomaterials for skeletal repair and regeneration? Solution Wolff\'a law was proposed by German surgeon Jullies Wolff. According to this law bone in an healthy person adapts to forces and stresses on which it is placed. If loading on a particular bone increases, the bone will remodel itself over time to become stronger to resist that sort of loading. The racquet-holding arm bones of tennis players become much stronger than those of the other arm. Their bodies have strengthened the bones in their racquet-holding arm since it is routinely placed under higher than normal stresses. This law is important in the designing of biomaterials because it helps us understand phenomenon of bone remodelling and how bone adjusts to different types of forces Bone constantly undergoes the process of remodeling. This process consists of two stages: resorption and formation. During resorption, old bone tissue is broken down and removed by special cells called osteoclasts. Once this has been done, bone formation begins and new bone tissue is laid down to replace the old. This task is performed by special cells called osteoblasts. Osteoblasts produce collagen, enzymes, and other proteins that make up the organic portion of the bone matrix.” It is important for the bone to access the information ,where the areas of stress are going to be so that bone can remodel and strengthen in preparation for the event. Bone cells, in particular osteocytes, are extremely sensitive to mechanical stress. Wolff law helps us to design biomaterials according to the stress it will undergo in the body..

1. What specialized cells line the inner cavity and move fluids through filter feeding sponges?
Solution
Collor cell:- Choenocytes
these cells are lying interenal side of the sponges having flagella and fibril like wall that trap
food particle that was coming thorough water current. these cells are unique for these porifera
phylum.