WILL GIVE BRAINLIEST
Which of these is the human body's first line of defense against invading pathogens such as bacteria and viruses?
a. macrophages
b. skin cells
c .vitamins

it's anything that aren't producers and consumers.

explanation:

you've got to be clear on what "this" is

some fungi obtain their nutrients from a living host (plant or animal) and are called most biotrophic fungi have fairly narrow host ranges—they are specialized on a limited called rhizomorphs that allow the fungus to grow from one tree to another. ascospores are formed inside a sac-like structure called an ascus. so your answer is a

blood enters the heart through two large veins, the inferior and superior vena cava, emptying oxygen-poor blood from the body into the right atrium of the heart. as the ventricle contracts, blood leaves the heart through the pulmonic valve, into the pulmonary artery and to the lungs where it is oxygenated.