What groups of organisms did Antonie van Leeuwenhoek discover with his homemade microscope?

Can someone me with questions 15 to 17 plz.

The organism shown is a free-living one that is anchored to the bottom of ponds and streams during one stage of its life cycle what is the common name for the group to which this organism belong

Select the correct answer a modure consists of glucose and water. what is the percent composition of glucose in the mixture if it contains 1.3 moles of glucose (cho total mass of the mature is 276 grams? ) and the a 1775