You are presented with the question "What inside of a shell requires warmth to survive?" and the following answer choices: 
- oysters
 - abalone
 - bullfrogs
 - sand
 - beads
 - water
 - embryos
 - Echinoids

Now knowing that an egg requires warmth to survive and inside of the eggs, the embryos grow by shedding their inelastic shell or exoskeleton, choose the best answer.


 

       embryos  