Answer:
The correct answer is 1 millon years.
Explanation:
Fossil rocks serve to study the evolution of species throughout history. Species usually adapt to survive the changing environment around them. Given this fact, we can deduce that the oldest species were very different from the way they are today. This means that the current species are more similar to those that preceded them more recently. The fossil of 1 million years ago is the most similar to today's horse.
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Answer:
Mass = 160 g
Explanation:
Given data:
Number of moles of sodium hydroxide = 4 mol
Mass of sodium hydroxide = ?
Solution:
Formula:
Mass = number of moles × molar mass of sodium hydroxide
Molar mass of sodium hydroxide = 40 g/mol
Mass = 4 mol × 40 g/mol
Mass = 160 g
<span>we are going to use H-H equation:
PH = Pka + log[conjugate base]/[weak acid]
when we have here the conjugate base is NaF
and the weak acid is HF.
so, we are going to use the Ka value to get the value of Pka.
when Pka = -logKa
= -log7.2 X 10^-4
= 3.14
then we will substitution on H-H equation:
</span>∴<span>PH = 3.14 + log (0.623)/(1.41) = 2.99</span>
It is under the condition when amount of available plankton is greatly reduced that competition among fish most likely to occur. Hope this answers the question.