Neutrophils engulf microbes by phagocytosis to fight an infection. Normally, they perform this function for some time but then die off. These dead cells and other foreign materials form pus. What cells then clean up all the dead neutrophils?

Macrophages engulf the dead neutrophils and the process is known as Phagocytosis.

Explanation:

Neutrophills are white blood cell that are produced by bone marrow which is released into the blood stream and they have short life span as they die in 1 day.These neutrophills along with other WBC are engulfed by macrophages which are also freely moving on the blood stream.

These mature macrophage plays a crucial role  as it locates the foreign body and eat them.

They use the process of phagocytosis and engulf the unwanted particles.

When the macrophages engulf the particle,phagosome is formed which is a pocket like structure then lysosome release enzymes that digest the particles.

americans began to notice growing differences between the northern and southern sections of the country. there were more people living in cities in the north, which made it more urban. more people lived on farms in the south, which made it more rural. while many people were farmers in the northern states, there were now other ways to make a living, such as working in mechanical cotton gins factories manufacturing cloth, tools and other goods. people in the north supported high tariffs on goods imported from europe because the extra cost encouraged people to “buy american” instead. in the southern states, planters did not like tariffs because they sold most of their production to europe and bought their tools from there as well. southerners believed the protective tariff was something that only northern factory owners keep their profits high. so the southern politicians came up with an idea. they would opt out. they would simply ignore the protective tariff. it was ‘null and void’ in south carolina. the state would not collect the taxes on goods imported into south carolina, no matter what the president said they had to do. this decision led to the nullification crisis.