The lines from the poem "Thrushes" discuss the nature of the thrushes and their daily activities. The phrases "single-mind-sized skulls," "trained Body," "genius," and "nestful of brats" suggest attributes or qualities that contribute to the thrushes' sense of purpose.
‘Single-mind-sized skulls’ refers to the thrushes' focus or concentration.
‘Trained Body’ implies the thrushes’ physical prowess or skill.
‘Genius’ might refer to their instinctive behaviors or intelligence.
‘Nestful of brats’ could imply their motivation to provide for their young.
Options Breakdown
Option I: Human beings and their intelligence
The passage is about thrushes, not humans. So, this option is incorrect.
Option II: The thrushes and their concentration in achieving what they set out for
The term “single-mind-sized skulls” highlights the thrushes' focused nature, so this is correct.
Option III: The efficiency of the thrushes in getting at their prey
The reference to a "trained Body" and "genius" relates to their efficiency and skill in hunting or performing their daily tasks, so this is also correct.
Option IV: All of the above
This option includes the above points, which are partially correct but not all.
Correct Answer: 4 (II and III are correct)