C) floatation
Floatation<span> is a separation process in which </span>minerals<span> that are valuable are separated from worthless material or other valuable </span>minerals<span> by inducing them to gather in and on the surface of a froth layer</span>
Answer:
C. At least five mass-extinction events have occurred during the last 500 million years.
Explanation:
- The history of mass extinct is related to the five mass extinctions that are caused over by the 350 million years n which many species have disappeared in there short geologic time.
- A massive extinction is caused in the Permian Triassic extinction event i.e about 250 mn years ago which on an estimate has killed 90% of the species.
- The Cretaceous–Paleogene extinction event that occurred over 66 million years ago is known to have wiped out the dinosaurs and many other species.
The genotype of the mother must be heterozygous.
<h3>Punnet' square</h3>
In order to obtain a probability of 25% red-eyed males from the offspring, the mother must be heterozygous for the trait. The father can be of any genotype.
Thus, the likely genotype combination that will result in 25% red-eyed males are:
x 
- and
When you cross the first one above, the genotype of the offspring would be 
.
The second cross will give offspring with the genotypes 
Both crosses give a 25% chance of producing re-eye males.
More on Punnet's square can be found here: brainly.com/question/3154616
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