Answer:A
Explanation: because The nucleus directs all of the cell's activities, including reproduction.
Answer:
<h2>500 J</h2>
Explanation:
The kinetic energy of an object can be found by using the formula

where
m is the mass
v is the velocity
From the question
m = 1.6 kg
v = 25 m/s
We have

We have the final answer as
<h3>500 J </h3>
Hope this helps you
Your question isn't quite clear, but if you're wondering if a chemical is polar or non-polar, you simply draw a VSEPR sketch and draw arrows where the bonds are. Only draw arrows between atoms, NOT between an atom and a lone pair of electrons. The arrow should point to the most electronegative atom (you should be given an electronegativity scale). Afterwards, you add up the arrows as vectors, and look at the sum of the vectors. If the sum is zero (CH4 is a good example), the chemical is non-polar. If the sum is a vector, the chemical is polar (H2O, or water, is polar).
Pure substances are substances which are homogenous in nature. They either consists of atoms of 1 kind or molecules of 1 kind. Atoms are seen in elements, where as molecules are seen in compounds like Acids, Bases, etc.
They mostly have fixed properties like boiling and melting points and are uniform in nature. :D