Part of a bird's digestive tract, called a gizzard, is able to break up large chunks of food at an extremely fast rate. It is difficult for scientists to watch a gizzard functioning in a live bird. How would building a model of a gizzard help a scientist?

relationships play a major role in a human's emotional and mental wellbeing. healthy relationships with the people around you are even linked to a smaller production of cortisol, a stress hormone.

the backbone of the dna and rna compound is sugar phosphate.

chert is a sedimentary rock composed of microcrystalline or cryptocrystalline silica. with this little bit of information, you can come to the conclusion that your answer is c.  

explanation:

answer : haversian

[explanation: -(compact bone is organized as parallel columns, known as haversian systems, which run lengthwise down the axis of long bones. these columns are composed of lamellae, concentric rings of bone, surrounding a central channel, or haversian canal, that contains the nerves, blood vessels, and lymphatic system of the bone)]