What are groups of like cells called?

A membrane refers to a structure that acts as a barrier or interface between different environments or compartments, such as the cell membrane that encloses cells. While membranes are crucial for cellular functions, they do not consist of groups of like cells, thus making this option incorrect.

A system is a higher level of organization that comprises multiple organs working together to perform complex functions, such as the digestive system or the circulatory system. Systems consist of various tissues and organs, but they do not refer specifically to groups of like cells, which is why this choice does not answer the question.

An organ is a collection of different types of tissues that work together to perform a specific function, such as the heart or liver. While organs are made up of tissues, they represent a more complex level of organization and do not define groups of like cells themselves, making this option incorrect.