The infective form of malarial parasite is :
**Core Concept**
The life cycle of the malarial parasite involves several stages, including the infective form that initiates the disease in humans. This stage is crucial for the transmission of malaria from one host to another. The **sporozoite** stage is the infective form of the parasite.
**Why the Correct Answer is Right**
The correct answer is the sporozoite because it is the stage of the parasite that is transmitted through the bite of an infected **Anopheles** mosquito. When an infected mosquito feeds on a human, it injects sporozoites into the person's bloodstream, which then travel to the **liver** to begin the next stage of their life cycle.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not represent the infective stage of the malarial parasite.
**Option B:** Similarly, this option is not the infective form.
**Option D:** This is also incorrect as it is not the stage responsible for initiating infection in humans.
**Clinical Pearl / High-Yield Fact**
Remembering that the **sporozoite** stage is the infective form of the malarial parasite is crucial for understanding how malaria is transmitted and how it can be prevented, such as through the use of insecticide-treated bed nets and **antimalarial prophylaxis**.
**Correct Answer:** D. Sporozoite