A group of similar cells working together is called:

1. Biological organisation runs from cells upward. 2. The level immediately above the single cell groups like cells together. 3. A group of similar cells working together is called a tissue. 4. Organs are built from several tissues, and an organelle is a structure inside one cell. _Source: OpenStax Biology for AP(R) Courses (CC BY 4.0), Ch 4 'Cell Structure', sections 4.1-4.6_