In Which organism always benefitted while the other organism is always harmed

List four observations that indicate that a chemical reaction may be taking place

Three alkali metals in group 1 are a. calcium, strontium, barium b. boron, aluminum, gallium c. sodium, potassium, rubidium d. fluorine, iodine, chlorine

Which of the following would be an accurate picture of the earth during the summer time of the northern hemisphere?