When a rock first formed, it contained 8 milligrams of potassium-40. How much potassium-40 would remain after three half-lives? 1 milligram
O 2 milligrams
O 3 milligrams
O 4 milligrams

An example of internal feedback working to maintain homeostasis is your a. decreased respiration rate when you are studying b. decreased heart rate when you are sad c. increased respiration rate when your muscles need more oxygen d. increased heart rate when your lungs need more oxygen

Identify characteristics of energy from the sun. check all that apply. almost all of the energy on earth comes from the sun. energy from the sun is known as mechanical energy. the energy in fossil fuels originally came from the sun. plants convert the energy of sunlight into chemical energy.

How would you describe the the organisms in the second row of model 1 that are connected to the parents by a line