Organs.
if you're having trouble remembering them they are
cell
tissue
organ
organ systems
organism
Answer:
A callus is a hardening of skin, keratin is the protein which is abundant in callus. Skin is a protective layer against a external environment. Outer layer of skin consist of keratin which is also found in hair. Callus is the accumulation of dead cells result due to friction and pressure exerts on the part in which they are present. The keratin component (keratinocytes) remains undifferentiated in these dead cells which causes hardening in callus.
What is the question you have?
C) Renal pelvis is the part of the kidney that acts as a funnel to pass the urine that is produced in several nephrons to the ureters.
