What are the advantages and disadvantages of a three chambered heart?

Explanation:

So a heart with three chambers is ideal for the needs of amphibians who could also absorb oxygen through their skin when moist.

The disadvantage of the three-chambered heart is the mixing of oxygenated and deoxygenated blood

"do a testcross with a homozygous recessive plant."

i believe it's c. the trait for large beaks will be passed on to future generations through natural selection.

since eventually smaller beaks would have to find another source of food or even eventually just die out from the lack of food.