Where should the biosphere label appear in the system model? Use reasoning to explain your answer.

Biosphere is the one of the sphere of geological sphere of the earth such as geosphere, hydrosphere and atmosphere. It is deal with the interaction and existence of the living organisms.

In this model it can be seen that there are human, fishes, and vegetation of plants are living organisms so living organisms in the hydrosphere (fishes), geosphere (plants) and anthrosphere (human) should be label as biosphere instead of atmosphere or with atmosphere.

"do a testcross with a homozygous recessive plant."

you know they are heterozygous for a trait because they have it as jj or jj.