Hormones
The endocrine system includes various glands in the body that are responsible for secreting hormones into the bloodstream. Hormones are chemical substances produced by the body that regulate certain functions of cells and organs. Hormones can regulate sleep, sex, growth, stress, huger, metabolism, etc.
According to the Doppler effect, the sound of a police car siren is louder and high pitched as it approaches the observer.
Photosynthesis gives the plant food/nutrients to be able to survive. They make their own food
