Can someone me with tis science question

Carbon dioxide is a concern because that small percentage is building up year by year, ergo causing global warming. Even at low percentage levels, it can trap mass amounts of infrared radiation, and more heat is being kept in earth atmosphere, which should be reflected into space.

Hope this helps.

Plants need carbon dioxide for photosynthesis and they themselves produce oxygen for human beings to survive 

Neither model is able to show the reactivity of potassium.