At the microscopic level, various entities can be transferred between organisms, including:
Genetic material (DNA/RNA): This can be transferred between organisms, especially in bacteria, through processes like conjugation, transformation, or transduction.
Viruses: These can move from one organism to another, infecting cells and introducing their genetic material.
Proteins and enzymes: Some organisms can transfer specific proteins to another, which can then alter the recipient's functions or characteristics.
Microbes (bacteria, fungi, protozoa): These can be transferred through various means, including physical contact, ingestion, or airborne transmission.
Plasmids: Small, circular pieces of DNA that can move between bacteria, often carrying antibiotic resistance genes.
Prions: Misfolded proteins that can induce other proteins to adopt their misfolded state, leading to diseases like Creutzfeldt-Jakob disease in humans.
Nutrients and waste products: At a cellular level, organisms can take up nutrients or expel waste products, which might then be taken up by another organism.
The specifics of what is transferred depend on the context of the question and the organisms involved.