Answer:
<u>A</u>
Explanation:
The heart cells must contract simultaneously to move blood.
This means that it needs to act fast and efficiently.
Therefore, the connections among heart cells are characterized by :
- having many branches
- having many communicating junctions
The correct option should be <u>A</u>
Answer:
True.
Explanation:
It also affects your lungs by getting lung disease.
Answer:
b. a massive collapsed star
Explanation:
A black hole in the universe is nothing but a massive collapsed star. When the size of the star crosses a particular limit it cannot holds its mass and it collapses under it own self. This is called supernova. A black hole is actually a region in space where gravity is so strong that even light cannot escape through it. Gravity so strong because the matter has been pressed into a tiny space. hence option b is correct
