First, let's explain the variables. F means force, m means mass, and a means acceleration. F is measured in Newotns [N], mass is measured in kilograms [kg], and acceleration in measured in meters per squared second [m/s²].
Now let's mover on the first problem.
Given
m = 1000 kg
a = 3 m/s²
According to the second law of Newton, the force is equal to the acceleration multiplied by the mass.

The answer is 3000 N.
The second problem is smiliar.
Given
m = 70 kg
F = 250 N
We use the same formula from before, and use a bit of algebra to adapat it to our needs.

The answer is 24 1/7 s/m^2.
The environment affects natural selection. Speices need to adapt to changes in environmnet. The weaker organisms which fail to adapt to environment perish while the stronger ones who adapt to the environment survive. This is how environment affects natural selection.
I cannot come up with a reaction which you can convert directly from Al to H2O.
But you can convert from Al2O3 to H2O by adding HCL solvent.
Answer:
The answer to your question is HCl + NaOH ⇒ NaCl + H₂O
Explanation:
Data
Double displacement reaction
Balanced chemical reaction
HCl + NaOH ⇒ NaCl + H₂O
Reactants Elements Products
1 Chlorine (Cl) 1
1 Sodium (Na) 1
2 Hydrogen (H) 2
1 Oxygen (0) 1
As we can see, the reaction is balanced and the coefficients of all reactants and products are 1, but the number is not written in a balanced reaction.