Trong bảng tuần hoàn clo thuộc nhóm viia số electron lớp ngoài cùng của nguyên tử clo là

The  grandmother cell  is a hypothetical  neuronthat represents a complex but specific concept or object.[1]  it activates when a person "sees, hears, or otherwise sensibly discriminates"[2]  a specific entity, such as his or her grandmother. the term was in use at least as early as 1966 amongst staff and students in the department of experimental psychology, university of cambridge, england. a similar concept, that of the  gnostic neuron, was proposed two years later

I'm not sure but i will try to find out

The answer is the first option just took the test