What is the effect of eutrophication on water bodies?

Which of the following is responsible for the increase in soil salinity?

Observe the figure and answer the following questions.
$(i.)$ What ecological term is used to describe the $DDT$ accumulation at different trophic levels?
$(ii.)$ List any one effect of $DDT$ accumulation on birds.
$(iii.)$ Will $DDT$ accumulation lead to eutrophication?
$(iv.)$ Does it affect the $BOD$?
$(v.)$ Name a disease caused by the accumulation of any heavy metal.

The noise produced in an office is normally at the level of: (in $\text{ dB}$)

Find out what the terms 'algal bloom' and 'red-tides' signify.

One of the human diseases due to biomagnification of heavy metals is