What is true of experimental designs that are used in scientific research

Plz plz plz quick! 49 points for whoever which of the following statements about greenhouse effect is true? *life on earth is suffering because of greenhouse effect *the greenhouse effect is caused by human activity *all greenhouse gases are harmful *life on earth would not exist without the greenhouse effect

In addition to seeds, which of the following characteristics are unique to the seed-producing plants? a) sporopollenin b) lignin present in cell walls c) pollen d) use of air currents as a dispersal agent e) megaphylls

Cells are adapted to preform specific functions. which of the following terms refers to this capability?