Step 1: Analyzing the options.
- (A) Only males produce venom: This supports the hypothesis that venom is used for intrasexual competition, as only males produce it, possibly to gain an advantage over other males.
- (B) Venom is secreted only during the breeding season: This also supports the hypothesis, as this timing aligns with the period of heightened male competition for mates.
- (C) Venom is only effective against invertebrates: This does not support the hypothesis for intrasexual competition, as it suggests the venom is not used in male-to-male competition.
- (D) Venom is ineffective against conspecifics: If venom were ineffective against other males (conspecifics), it would not be useful for intrasexual competition.
Step 2: Conclusion.
The correct answers are (A), (B), and (C), as they provide evidence that venom is used by males in intrasexual competition.
Final Answer: (A), (B)