Parasitic Algae:

Parasitic algae are those algae that live on the surface of other plants or organisms and derive their nutrients from them. They are commonly found on the leaves, stems, and fruits of various plants. Parasitic algae can cause significant damage to the host plant, leading to reduced growth, decreased yield, and even death.

Examples of Parasitic Algae:

Two examples of parasitic algae are Cephaleuros and Harveyella.

- Cephaleuros: Cephaleuros is a parasitic alga that affects various plants, including citrus, avocado, and tea plants. It infects the leaves and stems of the host plant and forms a greenish or reddish-brown coating on their surface. The coating can cause damage to the leaves and stems, leading to reduced photosynthesis and growth. Cephaleuros can also affect the fruit of the host plant, leading to reduced yield and quality.

- Harveyella: Harveyella is a parasitic alga that affects various marine organisms, including seaweeds, corals, and mollusks. It forms a greenish or brownish coating on the surface of the host organism, which can cause damage to their tissues and organs. Harveyella can also affect the growth and reproduction of the host organism, leading to reduced population size and diversity.

Conclusion:

Therefore, the correct answer to this question is option 'C', both A and B, as both Cephaleuros and Harveyella are examples of parasitic algae.

What is the need of explanation here both are parasitic algae you can check the example of parasitic alagae