In very early human history, complex sanitation systems were not needed because settlements were usually very small, like the village shown below.
however, as cities became larger and population densities increased, one major advancement was the development of which to channel wastewaters away from human populations more effectively than in the past.
a.
fountains
b.
water towers
c.
sewer systems
d.
dams

i mean i gues

explanation:

the equation above shows how temperature f, measured in degrees fahrenheit, relates to a temperature c, measured in degrees celsius. based on the equation, which of the following must be true?

a temperature increase of 1 degree fahrenheit is equivalent to a temperature increase of

5

9

degree celsius.

a temperature increase of 1 degree celsius is equivalent to a temperature increase of 1.8 degrees fahrenheit.

a temperature increase of

5

9

degree fahrenheit is equivalent to a temperature increase of 1 degree celsius.

a) i only

b) ii only

c) iii only

d) i and ii only

answer:

(b)

explanation: