the answer is a a and b beacuse c is a dumb answer and i had this question before hope it helps !!!
Answer:
Identifying elements in astronomical objects using their spectra. Measuring the spectrum of light from a star can tell astronomers what the star is made up of. Since each element emits or absorbs light only at a particular wavelength astronomers can identify what element are in the stars from the lines in their spectra.
This layer is C. Membrane. A cell or plasma membrane regulates what substances enter and what does not by controlling the movement of substances into and out of the cell.
1-no predators,so uncontrolled population growth
2-is a predator that is stronger than the apex predator of the area,or is in a predator free environment so has little to no problem spreading
3-is a toxic animal that breeds quickly,so when eaten can kill what ate it,there for ruining the ecosystem as the predators die from the toxic prey they eat.which can lead to method 1 if not dealt with.
