Which of these provides most of the oxygen in Earth's atmosphere? coral reefs
rainforest plants
ocean phytoplankton
continental grasslands

What food can provide the body with a quick source of the energy needed to carry out cell functions (a) whole grain bread (b) ground hamburger (c) vegetable oil (d) whole milk

When a human or animal consumes food, the carbon in that food is most likely to be converted into which of the following elements? a. carbon remains carbon b. nitrogen c. oxygen d. hydrogen

What molecule does hemoglobin decay into over time