Answer:
Solar flare
Explanation:
They are characterized by coronal mass ejections on the sun's surface. The ejected ionized particles if thrown in the direction of the earth will cause bright aurora as they colide with the earth’s ionosphere and magnetic field. These solar storms can also affect telecommunications satellites and also electricity grid systems.
It is not it something like sand because it would keep the fossil preserved.
Explanation:
the statue I am a pro is the size of the path of the world is not done so far
Answer:
b). activation of T cells
Explanation:
An APC (antigen-presenting cell) can be described as an immune cell, which detects, uptakes, and informs the acquired immune response when an infection takes place. B cells, macrophages, and dendritic cells are antigen-presenting cells.
These cells play an important role in activation of T cells. T cells are unable to recognize soluble or free antigens and can only recognize antigens processed and presented by carrier molecules, such as MHC molecules.
Presence of MHCII molecules is a defining feature of APCs that process and present antigens to T cells. Hence, all antigen-presenting cells help in activation of T cells.
Thus, the correct answer is option (b).