Answer:
3.9 billion years
Explanation:
The half-life of potassium-40 is the time it takes for half of it to decay.
After one half-life, half of the original amount will remain.
After a second half-life, half of that amount will remain, and so on.
We can construct a table as follows:

We see that the mass will drop to 10 g after three half-lives.
1 half-life = 1.3 billion years
3 half-lives = 3.9 billion years
Answer:
interfere with carbohydrate digestion in the mouth..
Explanation:
A blockage of the ducts from the parotid glands would interfere with carbohydrate digestion in the mouth.
In DNA Nucletide monomer are linked to the next through covalent bonds
Hope this helps!
Well, considering that seagulls, bears, and cows are warm blooded mammals, and spiders are arachnids with an exoskeleton, I'm willing to bet that spiders are ectothermic. And isn't the word exothermic?