Which gas makes up 78 percent of our atmosphere? It can be used by plants only when transformed by bacteria or lightning. oxygen
nitrogen
hydrogen
carbon

The image shows embryos of three vertebrate classes

Which organism is the producer in this food web? 7th grade question. a) arthropods b) birds c) fungi d) plants

Harold makes a venn diagram to him compare and contrast mitosis and meiosis. which label belongs in the region marked z? forms diploid cells creates an even number of cells includes two rounds of cell division duplicates body cells