Hypothalamus is a part of the brain that links the nervous system to the endocrine system via the pituitary gland. It helps maintain the internal environment constant by regulating major processes in the body such as the heart rate and the body temperature. It is therefore, both a neural and endocrine organ.
        
             
        
        
        
Answer:
1) types of music - independent 
performance in doing homework - dependent
person - control
2) period of time - control
number of flowers - dependent 
types of rose bushes - independent 
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Answer:
Well for one photosynthesis gives out oxygen. This makes all animals able to live. So in that way it helps us and the world around us. Without photosynthesis we also could not eat food. No animals could live and no plants ould live. VERY IMPORTANT!
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Clues such as fossils such as bones, footprints, tar, etc,  preserved underground helped inform scientists. You can also count how old a tree is when you cut it open and there are some alive for thousands of years so that is a possible way.