The question is confusing and all the answers are not there but it is B C and D
Answer:
55,000,000
Explanation:
550 hectometers [hm] = 55,000,000 millimeters [mm]
Covalent bonding is when electrons are shared between atoms.
Answer: Memory B and memory T cells are types of lymphocytes.
Explanation:
Memory B cells forms the part of adaptive immune system. These cells develop inside the germinal centers of the secondary lymphoid organs. These cells circulate in the blood. These are produced by the bone marrow and can be found in tonsil and spleen. Memory B cells are responsible for recognizing previous infections with a foreign antigen and prepare antibody against the new infection. Memory T cells recognize the antigen lived in the body for longer and produce quick response against it on second exposure. These are one of the types of T lymphocytes.
Should be :
Lead Sulfate Tetrahydrate
