What can happen when untreated sewage contaminates water?
erosion can increase.
o bacteria and viruses can spread.
heat pollution decreases.
o silt and suspended particles settle to the bottom.

Bacteria And Viruses can spread.

Step-by-step explanation:

Sewage is treated for bacteria, chemicals, and much more.

If this is not treated the sewage overflows with harmful bacteria. This gets into the water that we drink and can cause lots of things harm.

Hope I could help!! Have a great day!

m∠5 + m∠3 = m∠1   is true.

m∠5 + m∠6 = 180 is true

m∠2 +m∠3 = m∠6   is true

m∠2 +m∠3 +m∠5 = 180   is true