Which of the following is the correct statement with regard to fossils?

Bone is considered a composite material consisting of both inorganic and organic components. 

They are made up of connective tissues reinforced with calcium and specialized bone cells.

However, the fossil record is not only incomplete but has also inherent biases due to geological, physical, chemical and biological factors. 

Our knowledge of past life is also biased because of differences in academic and amateur interests and sampling efforts.