A. The bubbles are lighter than air.
B. There is matter that cannot be seen inside the bubbles.
C. The bubbles will burst before long.
D. The bubbles cannot be broken into smaller pieces.
Answer:Flouride it creates enamel.
Explanation:
enamel (that's the tooth's hard outer surface) more resistant to acids produced by the bacteria living on the teeth and gums.
Here are the list of nucleo bases : adenine , Thymine, Guanine , Cytosine
Adenine pairs with Thymine, and Guanine pairs with Cytosine
Adenine + Guanine = Purine
Thymine + Cytosine = Pyrimidine
So the answer for number 1 will be : Purine, since Adenine is not the choice
And the answer for number 2 is Guanine
hope this helps
Answer:
C. Butanal , is the aldehyde
Explanation:
A . It is carboxylic acid : ---COOH group
B. It is Ester : ----COOR group , Here R = CH3
C. It is Aldehyde : -----CHO group
D. It is ketone : ----C=O group
See image :
I am pretty sure shellac they would use in World War II.