Which of the following does NOT increase water density?

Decrease in temperature

Increase in water salinity

Increase in biomass

Increase in pressure

Increase in biomass

Explanation:

All the other choices have attributes that influence the density property of water except biomass. Biomass is organic material / matter that is mainly carbon-based - mainly derived from plants and animals. This has no relationship to water density even when the biomass is in the water because it's only gets suspended like sediment and does not get dissolved in the water.