Intercalated disks are unique to cardiac muscles.
I would chose the 4th one because biome is made up of a bunch of little biospheres
Explanation: Bacteria are needed in the nitrogen cycle because plants and animals cannot directly use atmospheric nitrogen. Bacteria in the roots of plants trap nitrogen and convert it to ammonia and other nitrogen compounds which plants can then use to make protein
Surface tension of water is 72 dynes/cm<span> at 25°C . It would take a force of 72 dynes to break a surface film of water 1 cm long.
Hope this helps.</span>