Answer:
please tell me you know, my hands are literally shaking at how easy this question is
Step-by-step explanation:
the answer is photosynthesis is a way for plants to make oxygen
still not enough information? they convert carbon-dioxide and water into oxygen and sugar, so they eat the sugar making their own food, put plants are living if they eat sugar. so they also have cellular respiration from mitochindria (photosynthesis is from chloroplasts and chrolophyll inside the chloroplast) and plants BREATH OUT SOME CARBON-DIOXIDE and produce more Oxygen than carbon-dioxide, thus providing the earth with Oxygen