When an antigen attacks the body, it activates adaptive immunity. this adaptive immunity produces a strong response when it encounters the same antigen for the second time. which feature of adaptive immunity is essential for this kind of response?

the earth is thought to have been formed about 4.6 billion years ago by collisions from a cloud of hydrogen, helium, rock, ice and other materials. these were pulled together by gravity to form objects in and around earth like- asteroids and small early planets called planetesimals.

so, the best possible answer to this question will be option d- to harden materials to form different parts of earth’s layers

not sure what it is

1) a

2)c

3)a

4)c

5)b

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