Adrian caught a virus while staying with his grandmother. a few years later, his mother and sister got the same virus. this virus could spread through touch and direct contact. however, adrian did not contract the virus this time, even though he was living with his mother and sister. why did he not get sick? adrian’s adaptive immunity remembered the antigens from the virus and gave him lifelong immunity to it. adrian’s innate immunity remembered the antigens from the virus and gave him lifelong immunity to it. adrian’s skin layer recognized the antigens and attacked them, which prevented the occurrence of the virus again. adrian’s innate immunity identified antibodies specific for the virus and targeted them against the antigen. adrian’s adaptive immunity produced a higher amount of specific antibodies for the antigen, preventing the virus. nextreset

The most appropriate answer would be the first option.

Adaptive immunity is a part of the immune system which protects our body against infectious agents with the help of  B lymphocytes and T lymphocytes.  

It is characterized by its memory that is, it creates the memory of a lifetime for particular antigen or pathogen once it has come across.

As Adrian caught the virus a few years ago his immune system had developed a memory for the virus.  

So, as soon as his body contracted the same virus his body recognizes it easily and produce quicker and higher amplitude immune response against it.

water is a polar molecule. a chemical bond is a force of attraction between atoms or ions. bonds form when atoms share or transfer valence electrons. atoms form chemical bonds to achieve a full outer energy level, which is the most stable arrangement of electrons. so, false

explanation:

in h2o molecule, two water molecules are bonded by a hydrogen bond but the bond between two h - o bonds within a water molecule are covalent. the greater the electronegativity difference, the more ionic the bond is. bonds that are partly ionic are called polar covalent bonds. nonpolar covalent bonds, with equal sharing of the bond electrons, arise when the electronegativities of the two atoms are equal.