A cow's<span> digestive system is quite different from that of humans. </span>Cows eat grass, hay and other plant material that contain hard-to-digest<span> cellulose. To cope with this </span>they<span> have a large stomach with four compartments, with the largest being the rumen.</span>
Answer:

Explanation:
The question will be easier to solve if we interpret it as, " How long will it take until one-fourth of a sample of the element remains,?"
The half-life of the element is the time it takes for half of it to decay.
After one half-life, half (50 %) of the original amount will remain.
After a second half-life, half of that amount (25 %) will remain, and so on.
We can construct a table as follows:


To balance the following chemical equation, make a tally or a count of each of the atoms on both sides of the reaction, and make sure that those atoms are equal on both the reactant and product side.
AL2O3 + HCl => ALCl3 + H2O
Left side. Right side
AL = 2. AL = 1
O = 3 Cl = 3
H = 1. H = 2
Cl = 1. O = 1
First balance the metal atoms, aluminum, then hydrogen and then oxygen.
Balanced equation :
AL2O3 + 6HCl => 2ALCl3 + 3H2O.
Left side. Right side
AL = 2 AL = 2
O = 3 Cl = 6
H = 6 H = 6
Cl = 6 O = 3.
Answer:
4FeS + 7O₂ ----> 2Fe₂O₃ + 4SO₂
Explanation:
You have to drag the elements shown on the right under the formula. For example, you would have to drag 4 of the FeS molecules under the 4FeS text in the formula. Then place 7 O₂ molecules under the 7O₂ text, etc.
It's a double replacement reaction, so
3 Ca(OH)2 + 2 H3PO4 --> Ca3(PO4)2 + 6 H2O
Ca3(PO4)2