The cells of the innate system recognize and respond to pathogens in a generic way, but, unlike the adaptive immune system (which is found only in vertebrates), it does not confer long-lasting or protective immunity to the host.ll white blood cells (WBC) are known as leukocytes. Leukocytes are different from other cells of the body in that they are not tightly associated with a particular organ or tissue; thus, they function similar to independent, single-cell organisms.
Ideally, the age to bring home a puppy is when heâs between seven and twelve weeks old. This is considered the critical socialization period in a puppyâs life, the time when he learns the most about his environment and begins to adjust to his surroundings.
There are some good reasons why you should not bring your new puppy home before he is 8 weeks old, but of course sometimes it just cannot be helped. A breeder may get taken into hospital, or even die, for example, and the distraught relatives need to rehome the puppies early.esist the temptation. If a breeder asks you to take a puppy home at five to six weeks of age, be very suspicious. Only in the most dire circumstances should a breeder let puppies go this young. Bear in mind that some disreputable breeders will make up excuses to get rid of puppies when they get to this age.