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. 

multiplying and dividing the two decimals and the eqations by the same number of the overalls

well for one plants are always the producer, so a is the answer. a wolf is more of the consumer(predator) and the deer is the prey so i know those two are out of the question. also mushrooms are fungi/fungus so a is the producer.