The answer is c, because we use it as an "index" to tell when the animal lived, so if it's unique to that time level in the ground we know it lived that long ago.
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A lawn mower works by converting chemical energy (energy stored in the gas) to mechanical energy.
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Answer:
d
Explanation:
HF gives its H to HPO42 making it H2PO4, so HF is the acid and F- is the conj base
Answer:
1.4e+8 bismuth atoms
Explanation:
If 10³ mm = 10¹² pm
then 44 mm = X pm
X = (44 × 10¹²) / 10³ = 44 × 10⁹ pm (which is the cookie diameter in picometers)
Now we can calculate the number of bismuth atoms needed to span the diameter of the cookie:
number of bismuth atoms = cookie diameter / bismuth atom diameter
number of bismuth atoms = 44 × 10⁹ / 320 = 0.1375 × 10⁹ atoms = 1.375 × 10⁸ atoms
And now to respect the answer format requested by the problem:
1.375 × 10⁸ = 1.375e+8 ≈ 1.4e+8