Because if you change two things then you do not know which one has affected or altered the dependent variable. if you only change one then you know what exactly changed and why
Answer:
E)Li
Explanation:
Electronegativity is the tendency of an atom to attract a pair of bonding electrons. In the periodic table, electronegativity increases across the period and decrease down the group.
This means the element at the top of the group would have the highest electronegativity.
The correct option is;
E)Li
Answer:
C
Explanation:
Alleles being more minute than genes,can pass on trait similar or different
Answer:
B. 
Explanation:
The unit for rate is M/s while the unit for each molecule should be M. You can find the unit for k by putting the units for rate and the molecules into the equation
rate= k{X][Y]
M/s= k *
* 
k= (M/s) / (
)
k= 
You can also use this predetermined formula to solve this problem faster: k= 
Where n is the number of molecule. There are 3 molecule(2X and 1Y) so n=3, so
k= 
k=
=
= 