Answer: The correct option is d. the improvement of the microscope and microscopic techniques.
In the 1600s the development of cell theory was led by advances in microscopy. The cell theory is historic in terms of scientific theory. According to the theory it was proposed that all living organisms are made up from cells, cell is the basic structural unit in all the organisms and new cells arise from pre-existing cells. The continuous improvement of microscopy with time and advancements in magnification technology were enough for discovering the cells and contributed the most towards the cell theory.
Answer: Each body segment of an earthworm contains four pairs of setae, which are used to move the worm. The setae of marine worms are found in bundles. Leeches do not have setae at all.
The correct option is A. Environmental DNA surveillance is used for detection and monitoring of invasive animal species in aquatic and terrestrial ecosystem. The surveillance method provides information for the management personnel about the existence of alien species or outbreak of diseases. Early detection is always crucial in this case in order to prevent fatal consequences.<span />
