Which of these is the beat example of a positive feedback loop in earth’s climate system

What correctly describes the relationship between the earth and the sun

Aneuron is stimulated with an electric pulse. the action potential is detected at a point 3.70 cm down the axon 0.0052 s later.when the action potential is detected 7.20 cm from the point of stimulation, the time required is 0.0063 s. what is the speed of the electric pulse along the axon? (why are two measurements needed instead of only one? )

Which of the following structures is not found in both plant and animal cells? a) chloroplast b) cytoskeleton c) ribosomes d) mitochondria