
Step 1: Identifying the Structure The given structure represents endomorphin, which is an endogenous opioid peptide found in the human body.
Step 2: Understanding the Source - Opium (Option A) is a natural source of morphine and related alkaloids but does not produce this specific structure.
- Frog-derived peptides (Option B) exist, but this structure does not match known frog peptides.
- Endogenous opioid peptides (Option C) such as endorphins, enkephalins, and dynorphins are naturally synthesized by the body and have similar structural motifs.
- Snake venom (Option D) contains various neurotoxins and peptides, but this structure is not related to venom-derived compounds.
Step 3: Selecting the Correct Answer
Since endomorphins are naturally occurring peptides in the body that exhibit opioid analgesic effects, the correct answer is: An endogenous compound present in the body (Option C).
If A + B means A is the mother of B; A - B means A is the brother of B; A % B means A is the father of B, and A \(\times\) B means A is the sister of B, which of the following shows that P is the maternal uncle of Q?