Active immunity will be the answer
Good luck:)
I think the answer is choice D
The correct one is Respiratory Distress !!
As rest are not concerned with air pollution !!
Connective tissue is developed from embryonic mesoderm. It often consists of interlacing protein fibers (though there are some exceptions, such as blood) that form a framework for and connect, support, separate, and bind tissues and organs in the body. Examples include cartilage and bone.
Hope this helps!
