I believe it may be carbohydrate as it contains part of the name of both elements
The two main tissues responsible for structural support in the body are called the compact bone and the ligaments.
The Compact bone is a dense bone in which the bony matrix is solidly filled with organic ground substance and inorganic salts, leaving only tiny spaces (lacunae) that contain the osteocytes, or bone cells.
A Ligament is a fibrous connective tissue that connects bones to other bones. It also supports the internal organs.
Answer:
I'm not sure I could say the sun because that's where the grass gets its energy but some people also would just say the grass but it's down to those two
They undergo photosynthesis by converting solar energy to chemical energy :p
Its a large nuclear pore
so pores :)