Photosynthesis is dependent on- A :the nitrogen cycle
B: ammonia
C: the seasonal cycle
D: the carbon cycle

How does the molecular clock work? a. it analyzes the brain functionality of two different species.b. it examines and compares the physical characteristics of two different species.c. it illustrates relationships between two different species.d. it compares the number of mutations that exist in the dna of two different species.

Can someone i have no idea of how to do this.

Is becoming less expensive to screen blood samples for dna certain diseases have genetic basis what is possible ethical concern about the availability of inexpensive dna testing