In a pyramid of numbers for figure 1 which organism would be at the base of the pyramid why?

In a pyramid of numbers, the organism at the base would typically be the primary producers, such as plants or phytoplankton, because they convert solar energy into chemical energy through photosynthesis. These organisms form the foundation of the ecosystem, providing energy for herbivores (primary consumers) that feed on them. Their abundance supports higher trophic levels, making them crucial for the structure of the pyramid.