<h2>Answer: Gravitational attraction
</h2>
Gravity force causes the clouds of dust and gas to form a protostar. As this <u>attraction force</u> is responsible for gathering and compressing the existing elements in the cloud of gas and dust, heating them during this process.
Then, when the amount of material accumulated by gravitational contraction is large enough, and the temperature and pressure reached high enough, the <u>nuclear fusion</u> process will begin.
To understand it better: The hydrogen nuclei will begin to fuse, generating helium nuclei in the process and releasing huge amounts of energy.
It should be noted that the protostars radiate half of the energy contributed by the gravitational collapse and the other half is invested in heating its core.
Answer:

Explanation:
Given:
Solute Diffusion rate = 4.0 × 10⁻¹¹ kg/s
Area of cross-section = 0.50 cm²
Length of channel =0.25 cm
Now for the new channel
Area of cross-section = 0.30 cm²
Length of channel =0.10 cm
let the Solute Diffusion rate of new channel = s
now equating the diffusion rate per unit volume for both the channels

thus,

A) Tolerance
Tolerance is developed after using a drug repeatedly, so the body adapts to it. Because of that, people who develop a tolerance would then need to use more of that drug to get the same effect.
Answer:
Part a)

Part b)

Explanation:
Part a)
For force conditions of two blocks we will have


now from above equations we have


now we know that


now from above equation we have


Part b)
When heavier block is removed and F = 908 N is applied at the end of the string then we have


