Red blood cells are produced in the body and travel through arteries and
veins to all of the major organs. The
circulatory system is able to maintain
a relatively constant amount of red
blood cells because red blood cells
are regularly produced by -
F the bones of the skeletal system.
G the lymph of the circulatory
system.
H the glands of the endocrine
system.
J the neurons of the nervous
system.

F. The Bones In The Skeletal System

Explanation:

Most of it is produced in the bone marrow inside the kneecaps

significant amounts of nitrogen oxides, carbon monoxide, and other pollution

explanation:

passenger vehicles are a major pollution contributor, producing significant amounts of nitrogen oxides, carbon monoxide, and other pollution. in 2013, transportation contributed more than half of the carbon monoxide and nitrogen oxides, and almost a quarter of the hydrocarbons emitted into our air.

the overall balanced equation

6co2 + 6h2o > c6h12o6 + 6o2

sunlight energy

where: co2 = carbon dioxide

h2o = water

light energy is required

c6h12o6 = glucose

o2 = oxygen