A level in an energy pyramid is called a level

What have we learned from fossil evidence about evolution? a) it is an abrupt change. b)the process is observable. c) it takes place during one lifetime only. d)the most complex traits are always selected.

Which of the following does not describe a physical property of iron? a iron is silvery-white or gray in color. b iron has a boiling point of about 3,000°c. c iron is a magnetic element . d iron and sulfur react to form iron sulfide.

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