2006-08-22 18:00:40 · 9 answers · asked by rhambass 4 in Science & Mathematics ➔ Chemistry
Periodic elements.
2006-08-22 18:11:49 · update #1
They are Hydrogen and Oxygen,,,,,,,,
becoz they form water molecule,,,,,,
But oxygen is helps to combustion,,,,,,,
and hydrogen is used to making hydrogen bomb,,,,,,
2006-08-22 18:13:15 · answer #1 · answered by Anonymous · 2⤊ 0⤋
Phosphorus and selenium are both toxic at sufficiently high concentrations- as are all of the elements. To paraphras Paracelsus, it's the dose that makes the poison. However, of the elements essential for human nutrition, phosphorus and selenium can be taken to extremes at lower concentrations than other elements- unless, of course, one considers fluorine to be essential, in which case fluorine (as gas) is exceedingly toxic.
Similarly, organophosphate materials (i.e., certain phosphorus compounds) are very good nerve toxins, as well as herbicides (Roundup). Again, the most toxic of these involve fluorine as well (Sarin, for example).
2006-08-22 18:26:48 · answer #2 · answered by Anonymous · 0⤊ 0⤋
Water and Air - I don't believe fire is essential to life.
Water in the form of floods and tsunamis and general drowning.
Air in the form of hurricanes etc.
2006-08-22 18:13:58 · answer #3 · answered by kimberhill 5 · 0⤊ 0⤋
I couldn't give two, but here is my top three Hydrogen, Oxygen, and Carbon provide air, water, and life building materials.
2006-08-22 18:13:03 · answer #4 · answered by icelusx 2 · 0⤊ 0⤋
Radium and Uranium
2006-08-22 18:05:11 · answer #5 · answered by akilashiva 2 · 0⤊ 0⤋
Air and water.
2006-08-22 18:05:56 · answer #6 · answered by The Apple Chick 7 · 0⤊ 0⤋
water and carbon dioxide
2006-08-22 18:13:23 · answer #7 · answered by I need Answers 5 · 0⤊ 0⤋
Water and Fire
2006-08-22 18:01:56 · answer #8 · answered by brad l 2 · 0⤊ 0⤋
tongue and lungs
2006-08-22 18:06:31 · answer #9 · answered by dale 5 · 0⤊ 0⤋