Why a plant leaf is not made of one GIANT leaf cell, but instead it is made of thousands of tiny cells that perform photosynthesis

Because all living things are made of cells. the cells help rebuild the plant if it has been injured just like humans. ex: if you scrape your arm, a scab will form and eventually your arm will be healed again. the plant does the same thing

Two types of bacteria do this job: non-symbiotic bacteria in the soil and symbiotic bacteria that live in the roots of plants. Bacteria in the genera Clostridium and Azotobacter are non-symbiotic nitrogen-fixing bacteria, while those in the genus Rhizobium are symbiotic bacteria.