Question

Of the following, which is the smallest parasite?

Answer 1

Parasites are organisms that feed on other organisms for their survival. These parasites can live inside of the body of the host for many years and even reach maturity inside their bodies. Parasites are found in a variety of different organisms like worms, insects, and bacteria. Majority of them are quite small.

Complete answer:
Of the given options all of them are flowering plants. Thus all of them are angiosperms. Angiosperms are the largest and most diverse group of plants on the planet. They comprise many different species that come in many different sizes. However only one of these plants is a parasite and that plant is the <>Arceuthobium_.
Arceuthobium : This is the smallest angiosperm parasite in the world. The Arceuthobium are a genus of parasitic plants that are also known as dwarf mistletoes. They live by using their host for nutrition.
Wolffia : Wolffia is the angiosperm that has the smallest flower in the world. Therefore at 0.1mm, this can be considered the smallest angiosperm in the world. However, this plant is not parasitic.
Lemna: The Lemna are small aquatic plants that live on ponds, but it is not as small as the Wolffia.
Spirodela : This angiosperm has one of the smallest genomes in the plant family. Some of the species in this family have a genome that is only 150 MB. But this plant is not parasitic.

Note:
The answer to the question given is Arceuthobium. This genus of parasitic plants is the smallest parasite in the angiosperm family. They typically use their roots to get nutrients like carbohydrates and minerals from the plant.