A Planaria worm is cut horizontally in the middle into two halves P and Q such that the part P contains the whole head of the worm. Another Planaria worm is cut vertically into two halves R and S in such a way that both the cut pieces R and S contain half head each. Which of the cut pieces of the two Planaria worms could regenerate to form the complete respective worms?
(a) only P
(b) only R and S
(c) P, R and S
(d) P, Q, R and S

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Solution

(d) P, Q, R, and S
Planaria are free-living flatworms that live in quiet ponds or bodies of water. They have the unique ability to regenerate, meaning they can re-grow the new tissue to replace lost or injured tissue.

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(d) P, Q, R, and SPlanaria are free-living flatworms that live in quiet ponds or bodies of water. They have the unique ability to regenerate, meaning they can re-grow the new tissue to replace lost or injured tissue.

(d) P, Q, R, and S
Planaria are free-living flatworms that live in quiet ponds or bodies of water. They have the unique ability to regenerate, meaning they can re-grow the new tissue to replace lost or injured tissue.