Name the first 20 elements of the periodic table.

Atomic NumberElementSymbol

1Hydrogen

2Helium        

3Lithium        

4Beryllium

5Boron        

6Carbon        

7Nitrogen        

8Oxygen        

9Fluorine        

10Neon        

11Sodium        

12Magnesium.  

13Aluminium

14Silicon        

15Phosphorus

16Sulfur        

17Chlorine        

18Argon        

19Potassium

20Calcium      

Explanation:

a: 45.9 meters

b: 4.29 seconds

step-by-step explanation:

a: h(t)=1/2(-9.8)(3)^2+0(3)+90

h(t)=-4.9(3)^2+90

h(t)=-44.1+90

h(t)=45.9 meters

b: 0=1/2(-9.8)(t^2)+0t+90

0=-4.9t^2+90

-90=-4.9t^2

18.37=t^2

t=4.29 seconds

in the second question, the numbers aren't exact, but they're a close approximation.

the food using pesticides in the future will harm you by giving you diseases like cancer or something since they have things that we should not eat in it like chemicals or pesticides. that is why organic food is more expensive because they take the time to make it right and healthy for you to eat.

explanation: