Final answer:
Many secondary alkaloids found in plants are poisonous to the nervous system, targeting insects, mammals, and potentially bacteria. The correct answer is option (a)
Step-by-step explanation:
Many secondary alkaloids found in plants are poisonous to the nervous system. These alkaloids serve as chemical defenses against pests and predators. The organisms targeted by alkaloids include insects, mammals, and potentially bacteria.
When insects consume plants containing alkaloids, the alkaloids can disrupt their nervous system and lead to paralysis or death. For example, nicotine is an alkaloid found in tobacco plants that acts as a potent insecticide. In mammals, alkaloids can also have toxic effects, affecting the central nervous system and causing various disorders or even death. For instance, morphine and heroin are alkaloids that can lead to addiction and have severe health consequences when consumed by humans.
It is worth noting that the specific effects of alkaloids can vary depending on the organism and the alkaloid involved. Some alkaloids may be toxic to one organism but not to another. Additionally, some alkaloids may have beneficial effects on certain organisms, such as acting as medications or spices for humans.