Mesoderm is the type of germ layer develops into bones, kidneys, bladder, ovaries or testes, blood, and muscles, including the heart.
Answer: Option A
Step-by-step explanation:
The end of the gastrulation phase of living organism is marked by the formation of three germ layers namely ectoderm layer, mesoderm layer and entoderm layer.
Each of the layers which are mentioned gets converted into different structure. The Mesoderm gets converted to connective tissue, ligament and smooth muscles. The heart dividers by blood, lymph vessels and cells.