Answer:
Offspring of a horse and donkey are unable to reproduce.
Explanation:
The biological concept of species states that:
A species is a group of organism with similar characteristics, that can interbreed and have a fertile offspring.
Horse + donkey = mule. A mule is a hybrid and is not fertile.
Explanation:
Metabolism in eukaryotic cells depends on the endoplasmic reticulum because it transports materials between membrane-bounded organelles within the cell.