An organism benefits from organ systems that work together and communicate, because these systems help an organism to
a. maintain heterogeneity.
b. maintain homeostasis.
C. carry out cell differentiation.
d.carry out complex, specialized functions.

Troposphere - It is the lowest layer of Earth's atmosphere and site of all weather on Earth.

Stratosphere - It is the second major layer of Earth's atmosphere, just above the troposphere, and below the mesosphere.

Ozone layer - It is a thin part of the Earth's atmosphere that absorbs almost all of the sun's harmful ultraviolet light.

Greenhouse gases - Water vapor, Carbon dioxide, Methane, Ozone, Nitrous oxide, Chlorofluorocarbons these are greenhouse gases.

Point and non point sources for pollution - Point-source pollution is easy to identify. As the name suggests, it comes from a single place. Nonpoint-source pollution is harder to identify and harder to address.

Primary pollutants - Nitrogen oxides(NOx), Carbon monoxide(CO), Volatile organic compounds(VOCs), Sulfur oxides (SOx), Particulate matter (PM), Mercury and more are primary pollutants.

Secondary pollutants - It is formed when hydrocarbons(HC) and nitrogen oxides(NOx) combine in the presence of sunlight.

Particulates(SPM or PM) - These are microscopic particles of solid or liquid matter suspended in the air.

VOC’s - VOC's are organic chemicals that have a high vapour pressure at room temperature.

Sulfur dioxide(SO2) - It is a toxic gas responsible for the smell of burnt matches.