Answer:
sarcomeres
Explanation: A contracting skeletal muscle fiber typically shortens as all of its sarcomeres do this.... Thick and thin protein filaments in sarcomeres interact to cause.... True or false, thick and thin filaments maintain their same length whether the muscle is relaxed or contracted?
There are called the stomata
Sources of heat from inside earth is radioactive decay and residual heat.
Explanation: some cells are specialized to do certain stuff. Like the breaking down of glucose wouldn't happen in the cells found in your leg.
Answer: https://www.wwf.org.uk/learn/wildlife/polar-bears#:~:text=Challenges%20affecting%20polar%20bears&text=The%20Arctic%20is%20warming%20about,ice%20to%20raise%20their%20young.
https://www.carbonbrief.org/polar-bears-and-climate-change-what-does-the-science-say
Explanation: