At what stage of pregnancy does an embryo show a beating heart and a complete central nervous system

Amale bird-of-paradise uses a dance to attract mates in which it flaps its tail feathers on the ground and jumps around a potential female mate. a different male bird-of-paradise does a similar dance but it jumps around the female in the opposite direction. the female bird is only attracted to one style of dance, in one direction. this is an example of speciation.

According to this food web which of the following would be considered primary consumers

Me the formula cacl2 represents the compound