The image shows a hand nurturing a plant. its purpose is to persuade people to take care of earth. what is this visual an example of?
here are the following choices:
a. semiotics
b. logos visual
c. rhetoric

If the image shows a hand nurturing a plant, with the purpose to persuade people to take care of Earth, this is a visual example of C. rhetoric, or to be more precise, visual rhetoric.
Rhetoric is used with one purpose mostly - to persuade. So this would be the correct answer.
Semiotics is simply the study of meaning, whereas logos visual are just logos. 

Undifferentiated cells eventually specialize into different types of cells, which make up different tissues. Those tissues later develop into organs.