15. Which of the following sources of pollution is currently considered the dominant source of carbon dioxide? (a) Cellular respiration (c) Combustion of fossil fuels (b) Freshwater sources (lakes, streams) (d) Photosynthesis

c) Combustion of fossil fuels

Explanation:

Burning of fossil fuels is the main cause of increasing carbondioxide concentration in the environment which results in air pollution. This increase in carbondioxide concentration absorbed more heat energy from reflected solar radiation which increases the temperature of earth surface causes global warming. Due to this global warming, snow melting occurs on the poles of the earth which increases sea level.

a. suckling by young

b. hypothalamus

c. dopamine

d. trh

e. anterior pituitary

f. mammary glands

g. milk production