Mutagens are: a)
chemical factors like radiomutation
b)
external factors responsible for tissue changing
c)
factors responsible for formation of mutation in the cell
d)
those which are responsible for formation induced mutation
e)
factors which act against the formation of mutation
f)
chemical factors like yperite or coffin
g)
genes responsible for formation of mutation
h)
physical factors like ionizing radiation

c)

factors responsible for formation of mutation in the cell

Explanation:

hope this helps

answer: - few nutrients

high pressure

low temperatures

explanation: 1. few nutrients:   open-ocean zone is located way far from the land, which is the main source of the essential nutrients.2. high pressure: pressure increases by 1 atmosphere for every 10 meters increase in depth.3. ample sunlight: a large fraction of the sunlight is reflected back to the atmosphere from the sea surface. 4. varying salinity: below the thermocline, the water is isolated from the atmosphere so the salinity remains stable over the year.5. low temperatures:   the temperature of open-ocean zone ranges from a low of -2°c to an average of 17°c