I think it's because of their range of tolerance.
1. The heart muscle cells need plenty of oxygen and nutrients so it needs its own blood supply.
2. The heart needs to have a blood supply to get ride of wastes.
Hope that helps. -UF aka Nadia
Answer:
Winters would be cooler and summers warmer because of the closer proximity of the Earth to the Sun.
Explanation:
Right now in the Northern hemisphere of the earth in July is the summer, the hottest season of all, and in January it´s winter the coolest season of all, so if 13,000 years from now the earth will be closer to the sun in july and more far away in january what this would do is create cooler winters, and warmer summers.
Answer:
The answer to your question is: two
Explanation:
Sucrose is a disaccharide composed by two disaccharides: glucose and fructose. Sucrose is found in plants. Its molecular formula is:
C₁₂H₂₂O₁₁