Answer:
if an animal lives in the desert and its moved to a cold place it can die cuz its not where it should be
Explanation:
Answer:
d. They always invade the human body from the external environment
Explanation:
Antigens are the molecules that have the ability to stimulate immune response and are mostly protein in nature. However, an antigen may be self or non-self molecule.
This means that antigen may enter the human body from the external environment (the non-self antigen) or any molecule present inside the body may serve as antigen (self-antigen). Self-antigens are responsible for autoimmune disorders.
Very sorry if this is wrong but I believe the answer is C!
Answer:
A pteridophyte is a vascular plant that disperses spores. Because pteridophytes produce neither flowers nor seeds, they are sometimes referred to as "cryptogams", meaning that their means of reproduction is hidden. Ferns, horsetails, and lycophytes are all pteridophytes.
Explanation: