Slime mould differ from fungi in having

The correct option is Both (a) and (b).

Let us understand the detailed biological differences between slime moulds and true fungi to see why this is the correct choice:

1. Phagocytosis Mode of Nutrition:
True fungi are heterotrophic organisms that exhibit absorptive nutrition (osmotrophy). They secrete digestive enzymes externally into their environment to break down organic matter and then absorb the dissolved nutrients through their cell walls.
In contrast, slime moulds (specifically in their plasmodial or amoeboid stages) ingest food particles, bacteria, and other microscopic organisms directly by engulfing them, a process known as phagocytosis (ingestive nutrition). This is a animal-like or protozoan-like characteristic not found in true fungi.

2. Amoeboid Cells:
During their vegetative phase, slime moulds exist as single-celled amoeboid structures (myxamoebae) or as a large, multinucleate mass of protoplasm (plasmodium) that moves via pseudopodia, lacking a rigid cell wall. This somatic state is highly motile and amoeboid.
True fungi, on the other hand, possess a cell wall made of chitin in their vegetative state and lack amoeboid stages in their lifecycle.

Therefore, slime moulds differ from fungi in having both phagocytic nutrition and amoeboid cell stages, making "Both (a) and (b)" the correct option.