The respiratory system always needs iron. The red blood cells are in charge of the transport of O2. They need iron to do this.
Hope this helps! :)
Energy would have to be the correct answer
We know that Hardy-Weinberg conditions include the following equations:

where 
And where p = dominant, and q = recessive; this means that
is equal to the homozygous dominant,
is the heterozygous, and
is the homozygous recessive .
So we have 100 total cats, with 4 having the recessive white coat color. That means we have a ratio of
or 0.04. Let that equal our
value.
So when we solve for q, we get:


Now that we have our q value, we can use the other equation to find p:



So then we can solve for our heterozygous population:

This is the ratio of the population. So we then multiply this number by 100 to get the number of cats that are heterozygous:

So now we know that there are 32 heterozygous cats in the population.
Answer:
I'm going to say grass
Explanation:
Didn't post food chain but grass is a very commonly used producer.
The purine base adenine
The pentose sugar ribose
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Three phosphates </span>