Examples: The gene for seed shape in pea plants exists in two forms, one form or allele for round seed shape (R) and the other for wrinkled seed shape (r). A true-breeding round seed plant would be (RR) for that trait and a true-breeding wrinkled seed plant would be (rr).
The integumentary system consists of the skin, hair, nails, the subcutaneous tissue below the skin,and assorted glands.The most obvious function of the integumentary system is the protection that the skin gives to underlying tissues. The skin not only keeps most harmful substances out, but also prevents the loss of fluids.
As a whole, the integumentary system plays a big part in maintaining homeostasis. The integumentary system is the outermost organ system of the body and many of its functions are related to this location. The skin protects the body against pathogens and chemicals, minimizes loss or entry of water, and blocks the harmful effects of sunlight.