A person who has a weakened immune system may not be able to fight against infection because.. pathogens may enter the body and cause illness.
phagocytes many enter the body and cause illness.
normal cells crowd out unhealthy cells.
of an increase in the production of antibodies.

Pathogens may enter the body and cause illness

Explanation:

With a weak immune system, response to any pathogens may be weak as well thus giving them great chance to entire the body and cause illness

weathering - colorado river carves land in arizona to form the grand canyon. cracks form in a sandstone wall surrounding a house. a marble statue near the science museum is changing color due to rainfall

erosion - after a rainstorm, soil and rock piees litter the roadways. the sand dunes in the sahara desert are changing shape.

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