Why do scientists study earth as a system

Aeukaryotic cell must be from a plant if the cell a) a nucleus b) a nuclear envelope c) cytoplasm d) a cell wall

Indica el nombre y la fucion de los vasos sanguineos que entran y salen de los riñones

Which symbols below represent the ions found in the glass of water ? a. oh- and h+ b. co2 and o2 c. o2 and h2 d. nh3- and h+