Mercury, Earth, and Mars. Also Venus but that isn't an option.
Have a nice day :-)
Answer: Option A.
Different beaks were available
Explanation:
Variation is the difference between traits, cells, or characteristics between organisms of any species which is caused by change in genetic information or effect of environmental factors on the expression of genes.
From the question, different beaks were available because there is variation or differences in shapes, sizes and expression.
Nucleus. it’s the main part that sorts and tells cells what to do and where to go.
Stem cells are what allow planaria to grow and regenerate as the stem cells can change into any of the cells that make up the planaria.