Which of the formed elements of blood defends against pathogens?
white blood cells
red blood cells
antibodies
plasma

White blood cells

Explanation:

The white blood cells belongs to the solid parts of the blood which floats over the liquid plasma. These cells plays an important role in maintaining the immunity in the body of the living organisms. Types of white blood cells includes the granulocytes and lymphocytes. These cells fights against the disease causing pathogens present inside the body hence, provide immunity to the body.

the correct answer is: b. pantala flavescens, because these organisms would have a high level of genetic variation due to sexual reproduction.  

because involves two organisms (parents) whose genetic material combines, sexual reproduction leads to genetic variation in new generations of offspring. the offspring is an unique organism, with new genome, more protected with the higher ability to adapted. this process is fundamental to evolution.