Top 10 causes of death worldwide. Of the 56.4 million deaths worldwide in 2015, more than half (54%) were due to the top 10 causes. Ischaemic heart disease and stroke are the worldâs biggest killers, accounting for a combined 15 million deaths in 2015. These diseases have remained the leading causes of death globally in the last 15 years.
photosynthesis removes carbon dioxide from the atmosphere, and cellular respiration puts it back. Photosynthesis releases oxygen into the atmosphere, and cellular respiration uses that oxygen to release energy from food.
Photosynthesis uses water, sunlight, and carbon dioxide from the atmosphere to create glucose molecules, and releases oxygen as a by-product. Cellular respiration uses glucose molecules and oxygen to produce ATP molecules and carbon dioxide as the by-product. Photosynthesis takes place only when there is sunlight. Cellular respiration occurs at all times. Photosynthesis involves conversion of one type of energy into another: light energy into chemical energy. Cellular respiration involves using that chemical energy and breaking it down to release energy.