The core of a star must be at the temperature of 10,000,000 degrees Celsius for hydrogen fusion to begin.
1. Air pollution is a problem<span> because it can cause damage to animals, trees, plants, crops and water sources in the environment. </span>Pollution<span> in the </span>air<span> causes </span>problems<span> for aviation because it reduces visibility, while also being responsible for damaging buildings and other structures.
2. </span><span>The air we breathe has a very exact chemical composition; 99 percent of it is made up of nitrogen, oxygen, water vapor and inert gases. Air </span>pollution occurs<span> when things that aren't normally there are added to the air. A common type of air </span>pollution<span>happens when people release particles into the air from burning fuels.
3. </span>Pollution prevention (P2) is any practice that reduces, eliminates, or prevents pollution at its source. ... Reducing the amount of pollution produced means less waste to control, treat, or dispose of. Less pollution means less hazards posed to public health and the environment.
4. Why is it so important to have clean air?
Concaved lenses...........
Answer:
0.5 m/s².
Explanation:
From the question given above, the following data were obtained:
Initial velocity (u) = 0 m/s
Final velocity (v) = 10 m/s
Time (t) = 20 s
Acceleration (a) =?
Acceleration can simply be defined as the rate of change of velocity with time. Mathematically, it is expressed as:
a = (v – u) / t
Where:
a is the acceleration.
v is the final velocity.
u is the initial velocity.
t is the time.
With the above formula, we can obtain the acceleration of the car as follow:
Initial velocity (u) = 0 m/s
Final velocity (v) = 10 m/s
Time (t) = 20 s
Acceleration (a) =?
a = (v – u) / t
a = (10 – 0) / 20
a = 10/20
a = 0.5 m/s²
Therefore, the acceleration of the car is 0.5 m/s².
Explanation:
First we will convert the given mass from lb to kg as follows.
157 lb = 
= 71.215 kg
Now, mass of caffeine required for a person of that mass at the LD50 is as follows.

= 12818.7 mg
Convert the % of (w/w) into % (w/v) as follows.
0.65% (w/w) = 
= 
= 
Therefore, calculate the volume which contains the amount of caffeine as follows.
12818.7 mg = 12.8187 g = 
= 1972 ml
Thus, we can conclude that 1972 ml of the drink would be required to reach an LD50 of 180 mg/kg body mass if the person weighed 157 lb.