The correct answers are as follows;
1. The scientists that are credited for the events described in the developments of the cell theory are THEODOR SCHWANN, MATTHIAS SCHLEIDEN AND RUDOLF VIRCHAW. These three scientists contributed to cell theory in significant ways. In 1830, Matthias and Theodor proposed the unified cell theory based on their study of living tissues. This theory stated that all living things are made up of one or more cells, the cell is the basic unit of life and new cells come from pre-existing ones. Rudolf later on made important contributions to the cell theory.
2. ROBERT HOOKE was the scientist who use the word cell for the structure he observed when he was examining a piece of cork under the microscope. In 1665, Robert Hooke was observing a cork with lens in his laboratory, when he noticed that the cork is made up of compartments, which are linked to one another. He coined the word ‘cell’ as the name of the structures he observed in the cork.
3. The first scientist to observe a living cell in a drop of pond water was Anton Van Leeuwenhoek. The scientist had the habit of using lenses to study small living organisms in rainwater, well water and ponds. In 1674, he observed protozoa for the first time and later bacteria. His work helped to refute the principle of spontaneous generation and also served as foundation for the study of bacteria and protozoans.
4. The correct option is C.
Algal boom usually occur as result of eutrophication. The large mass of algae, which are formed on the water surface usually reduce the amount of light that can penetrate the water and consequently reduce the amount of oxygen that is dissolved in the water. This leads to the death of the animals living in the water, which in turn results in reduced biodiversity and water contamination.