They are held together by weak hydrogen bonds
They are found in any habitat but most live on lan, mainly in soil or on plant material
The correct answer is Protozoans.
Protozoans are best described as uni-celled eukaryotic organisms, both free-residing or parasitic, which feed on organic matter together with different microorganisms or organic tissues and particles. back then, the protozoa have been seemed as "one-celled animals," because they regularly possess animal-like behaviors, together with motility and predation, and lack a mobile wall, as discovered in plant life and plenty of algae.
Answer;
-Gametic Isolation
Explanation;
-Gametic isolation is a type of prezygotic barrier where the gametes (egg and sperm) come into contact, but no fertilization takes place.
-In Gametic isolation is when sperm of one species may not be able to fertilize the eggs of another species. For instance, sperm may not be able to survive in the reproductive tract of females of the other species, or biochemical mechanisms may prevent the sperm from penetrating the membrane surrounding the other species' eggs.