What are the answers given
Helps to reduce pollution in a community
Population is the term used for the organisms
Ice floats because it expands (kid version). The molecules are less dense in ice than when water (H2O) and the structure is different.
Hope that help
The eggs of the fluke are passed into water supplies from feces and urine of infected people. After hatching the parasite actively swims and invades the body of a snail, usually by penetrating through the snail's foot. The parasite requires the presence of certain species of snails (e.g., Oncomelania, Biomphalaria, Bulinus) to transform (and multiply) itself into an infective stage, called cercaria.