V11-19

Official Solution:

Whereas in mammals the heart, which has four chambers, two ventricles and two atria, delivers oxygenated blood to the organs by one channel while the other directs blood to the lungs for re-oxygenation, the reptiles have three-chambered hearts with two ventricles and only one atrium.

A. in mammals the heart, which has four chambers, two ventricles and two atria, delivers oxygenated blood to the organs by one channel while the other directs blood to the lungs for re-oxygenation, the reptiles have three-chambered hearts with
B. in mammals the heart has four chambers, two ventricles and two atria, and delivers oxygenated blood to the organs by one channel while directs blood to the lungs for re-oxygenation by another, the heart in reptiles has three chambers,
C. the mammalian heart, consisting of four chambers, two ventricles and two atria, delivers oxygenated blood to the organs by one channel, while the other directs blood to the lungs for re-oxygenation, the reptilian heart has three chambers,
D. the mammals have hearts consisting of four chambers, two ventricles and two atria, which deliver oxygenated blood to the organs by one channel, while direct blood to the lungs for re-oxygenation by another, the reptiles’ hearts have three chambers,
E. the mammals have hearts consisting of four chambers, two ventricles and two atria, delivering oxygenated blood to the organs by one channel, while directing blood to the lungs for re-oxygenation by another, the reptiles’ hearts have three-chambers,


A. The contrast using whereas must have two parallel elements. The heart (in mammals) is wrongly contrasted with the reptiles. Moreover, the contrast using while too must have two parallel elements. Faulty parallelism exists between delivers oxygenated blood to the organs by one channel and the other directs blood… .

B. Correct. The heart (in mammals) is correctly contrasted with the heart in reptiles.
Parallelism is maintained between delivers oxygenated blood to the organs by one channel and directs blood to the lungs for re-oxygenation by another.
C. The construction the mammalian heart… …..delivers oxygenated blood is wrongly contrasted with the reptilian heart has 3 chambers – the contrast is wrongly established between delivering blood and having 3 chambers. Faulty parallelism exists between delivers oxygenated blood to the organs by one channel and the other directs blood… .

D. The contrast is wrongly established between the mammals and the reptiles’ hearts. The modifier which deliver oxygenated….. by another wrongly refers to atria.

E. The contrast is wrongly established between the mammals and the reptiles’ hearts. The present participle (-ing) modifier delivering oxygenated blood………by another seems to refer incorrectly to the subject (the mammals) of the preceding clause – the mammals do not deliver oxygenated blood, their hearts do.


Answer: B