What scientist invented echo-sounding devices for mapping the ocean floor?

Which of the following is not a symptom of desertification? a) decrease in salt content of the soil b) lowering of the water table c) reduced surface water d) increased soil erosion e) loss of native vegetation

Consider the venn diagram of plant reproduction. where in this image, areas a - d, would you insert the picture of the orange lily?

The earth's oceans are made up of chlorine, and trace elements. a) carbon, oxygen b) oxygen, silicon c) hydrogen, oxygen d) nitrogen, oxygen