Answer:
1.A tissue is a collection of similar cells that work together to perform a specific job.
An organ is a collection of different tissues that work together to perform a specific job. The function of a part of an organism is what it actually does (it's job)
2.The structure of the alveoli as a web of blood vessels surrounding an air sac allows blood cells take in oxygen and bring it into the lungs (organ)
Answer: Dip tube. This tube, located at the top of the tank, serves as the entry point for water as it flows into the tank. The water then travels to the bottom of the tank, to the area known as the combustion chamber, where the heating process begins.
Explanation: Thats what the internet says, and the internet is almost always right, hope you get it right.