For an organ transplant, it is an advantage to have an identical twin. Why ?

Assertion $(A)$ : Antigen can be easily recognized because it has antigenic determinants.

Reason $(R)$ : The recognition ability is innate.

Humans have acquired immune system that produces antibodies to neutralize pathogens. Still innate immune system is present at the time of birth because it

Colostrum, the yellowish fluid, secreted by mother during the Inittlal days of lactation is very essentlal to impart immunity to the newbom infants because it contains

Antigen is a substance which