Diatomaceous earth is formed due to which substance?

The scientist who coined the term 'Protista' to include both plant-like and animal-like unicellular organisms was

"Red tides" are caused by .........

Which of the following statements are correct about slime moulds?
$(i)$ Its thalloid body,Plasmodium,has pseudopodia for locomotion and engulfing organic matter.
$(ii)$ During unfavourable conditions,Plasmodium differentiates and produces fruiting bodies,sporangia.
$(iii)$ Spores possess no true cell wall.
$(iv)$ They are dispersed by air currents.
$(v)$ Being extremely resistant,spores survive for many years.
$(vi)$ Plasmodium can grow up to several feet.
Choose the correct answer from the following options:

Which organism is considered a connecting link between protozoa and unicellular plants?

Which of the following animals are included in the class $Sporozoa$?