Generally, you can calculate it with this formula: df = (r-1)(c-1) where r is the number of rows and c is the number of columns.
Answer;
Cell
Explanation;
-The biological levels of organization of living things arranged from the simplest to most complex are: organelle, cells, tissues, organs, organ systems, organisms, populations, communities, ecosystem, and biosphere.
-Cell is the basic unit and building block of life. It is bound by a cell membrane, and possesses a nucleus which acts as its brain. Arachnoidiscus ehrenbergi is an example of diatoms which are unicellular, therefore it is a cell.
Answer: C). Sensory neurons, D).motor neurons
Explanation: Sensory neurons are nerve cells that carry signals from the external parts of the body such as the skin, eyes, ear, nose (the sense organs) to the brain.
Motor neurons are nerve cells that carry information or messages away from the central nervous system ( brain and spinal cord) to the rest of the body such as the skin, muscles and glands.