Answer:
oxygen, sulfur, selenium, tellurium, polonium, and ununhexium (O, S, Se, Te, Po, and Uuh, respectively)
Explanation:
i hope it helps all this are 6 valence from electron and form 2-iron.
Vaccines help develop immunity by imitating an infection. This type of infection, however, does not cause illness, but it does cause the immune system to produce T-lymphocytes and antibodies. Sometimes, after getting a vaccine, the imitation infection can cause minor symptoms, such as fever. Such minor symptoms are normal and should be expected as the body builds immunity.
D. controlled cell suicide
C. since sexual reproduction takes a lot longer and it involves 2 offsprings. it requires more energy
The effector in a negative feedback system acts to counter any changes made to a particular property. If it were positive feedback, it would amplify the change and make it more extreme
