1. Response to Shuhan's objection: Some beings need to fulfill their basic needs, like an animal needs to hunt for food, which is based on the death of another animal. We could not regard hunting foods as an immoral behavior, for feeling hungry and then eating food is the conditioned reflex of all beings’ physical response. We can then apply this situation to human beings that we, human beings, also need food to fulfill our basic need, and animals are one of the food sources for humans to stay alive.
2. According to Singer, sentience is sufficient for moral consideration. When an animal successfully gets its prey, it is attaining pleasure. Therefore, the attained pleasure and satisfaction make the animal spontaneously think it does nothing morally wrong. No matter it is “basic” needs or not, the outcome it brings is that the sentience, feeling pleasure, could help the creature to determine what’s morally wrong.