What could be some weaknesses with using a test cross to determine Fred’s genotype?

The disadvantage of this test and it's weakness is if there is a genetic trait with complete domination, then the plant with the recessive characteristic has to be acquired.

Explanation:

To determine a genotype is not that easy and effortless because you can't see the genes of one organism if you just look at it.

the earth is thought to have been formed about 4.6 billion years ago by collisions from a cloud of hydrogen, helium, rock, ice and other materials. these were pulled together by gravity to form objects in and around earth like- asteroids and small early planets called planetesimals.

so, the best possible answer to this question will be option d- to harden materials to form different parts of earth’s layers