Question

explain the emergence and purpose of the three primary germ layers by selecting each word or phrase to complete the sentences.

1. after the egg is fertilized, the first tissues that appear are called the click to select.
2. the click to select of the digestive tract emerges from the click to select.
3. muscle, bone, and blood all emerge from click to select, which is derived from the click to select layer.
4. all three primary germ layers give rise to click to select.
5. the brain and spinal cord are composed of tissue that arises from click to select.

Explanation:

1. After fertilization, the first - formed tissues are the primary germ layers.
2. The lining of the digestive tract comes from the endoderm.
3. Muscle, bone, and blood originate from mesenchyme which is from the mesoderm layer.
4. All three primary germ layers give rise to different types of tissues and organs during development.
5. The brain and spinal cord are made of tissue from the ectoderm.

Answer:

1. primary germ layers
2. lining; endoderm
3. mesenchyme; mesoderm
4. different types of tissues and organs
5. ectoderm