During the period of the embryo, the becomes the nervous system, the becomes the circulatory system, and the becomes the digestive system

Weeks 3-4: three layers form: the ectoderm, the mesoderm, and the endoderm. Neural tube develops and produces neurons. Heart begins beating. Ribs, muscles, and digestive tract form. weeks 5-8: arms and legs develop, then fingers and toes; placenta and umbilical cord function; digestive system develops; liver produces blood cells. 

1. a host loses nutrients to a parasite

2. a parasite only benefits when the host is alive (cause if the host dies the parasite dies with it )

3. producers to consumers

4. the tapeworm is a parasite

5. they convert energy from the sun (photosynthesis)

6. sunflower-robin (i think im 80% sure)

7. producer

8. consumer

9. prey

10. fresh water snails ( cause the green algea is the producer and the snails are the primary consumers and the small fish consumer so is the big fish)