Stars that are comprised of greater mass, probably about 20 times more than the mass of the sun can give rise to the formation of a black hole after the star dies off. There is a constant collision between the particles inside a star as the pressure and gravitational force acts over one another. The core of the star undergoes an extensive nuclear reaction that is responsible for the generation of a huge amount of energy that pushes in the outward direction. When a star uses all of its nuclear fuel, then gravity becomes more dominant and the core is compressed with more intensity, as a result of which the star gets collapse.
These are those supergiant stars that die off over a specific period of time and eventually forms a black hole.
An average person (let's say one that weights 70 kg) has about 5.5 liters of blood (that's a little more than 160 ounces or 1.2 to 1.5 gallons). Other way of saying this is : about 7% of body weight.
The correct answer is actin. Microfilaments are made form a ball-shaped protein called actin. These actins are globular proteins who are the ones responsible for the formation of microfilaments. It is mostly found in the eukaryotic cells.
