What is the role of the effector in a feedback loop?

Ihave no idea how to solve these. plus there's another question that is 2) a 10 kilogram meteorite is collected in space and brought back to earth. it is composed of 1.25 kg of uranium-238 and 8.75 kg of lead-206. how many u-238 half lives have passed? what is the approximate age of the meteorite?

In which energy level are valence electrons located?

Put the processes of the water cycle in the correct order starting at the point where the water is in a lake