Which cross would be represented as Aa × aa, where (A) represents a dominant allele and (a) represents a recessive allele?
Parental Feather Colors
Offspring Feather Colors
1 2 3 4
White × White White × White White × Dark Dark × Dark
100% White 75% White, 25% Dark 50% White, 50% Dark 100% Dark
A researcher sprays a new pesticide on thousands of insects of the same species that live in a large field. A few of the insects survive. What can be concluded by the researcher?
The species of insects will likely become resistant to the pesticide.
The ideal interval between the first and second applications of the pesticide should be increased.
The pesticide has no effect on the species.
The concentration of the pesticide was too weak.
North Carolina Test of Biology. Form I RELEASED Fall 2009
This chart shows the results of several crosses with white-feathered chickens and dark-feathered chickens.
According to fossil records, the horses that lived 50 million years ago were much smaller, weaker, and slower than modern horses. Which process is most likely responsible for the changes that have led to the increased size, strength, and speed in horses?
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