What is the role of T-cells in the humoral immune response? A) Helper T-cells are converted to B-cells following clonal selection. The B-cells are activated to produce antibodies following antigen recognition Effector B-cells undergo clonal expansion after receiving a signal from memory T-cells. D) The B-cells are activated after receiving an interleukin signal from an effector T-cell,​

When you push downward on a book at rest on a table, you feel an upward force. does this force depend on friction? defend your answer.

Electric field of the earth. the earth has a net electric charge that causes a field at points near its surface equal to 150 n> c and directed in toward the center of the earth. (a) what magnitude and sign of charge would a 60-kg human have to acquire to overcome his or her weight by the force exerted by the earth’s electric field? (b) what would be the force of repulsion between two people each with the charge calculated in part (a) and separated by a distance of 100 m? is use of the earth’s electric field a feasible means of flight? why or why not?

The electric potential v is constant everywhere within a certain region of space. which statement below is true? the choices are: the electric field is also constant (but not zero) within the region. a charged particle placed within the region will experience an electric force. the electric field is zero everywhere within the region. the electric field varies from place to place within the region.