Answer:
by testcrossing with a homozygous recessive partner
Explanation:
<u>If a pet cockroach exists whose zygosity is unknown, this can be determined by a test cross. A test cross involves crossing an organisms whose zygosity is unknown with a partner that is homozygous recessive for the same trait.</u>
Let us assume that brown body is represented by the allele B, the dominant allele. The homozygous recessive version would be bb.
The genotype of a brown cockroach whose zygosity is not known can be denoted as B_, where '_' can be a 'B' or a 'b'.
When B_ is crossed with bb:
B_   x   bb
Progeny
2 Bb 
2 _b 
The phenotype of Bb would be brown (since B is dominant over b) while the phenotype of _b would depend on the zygosity level of the cockroach. 
If the unknown genotype is BB, then _b becomes Bb and the phenotype will be a brown body. This means that all the progeny will appear brown. (<em>see the first attached image for the Punnet's square</em>)
In other word, if the unknown genotype is bb, then _b becomes bb and the phenotype will be a alternate color (non-brown) body. This means that 50% of the progeny will appear brown while the remaining 50% will be in the alternate color. (<em>attached</em>
 
        
             
        
        
        
Oncogenes are most like the gas pedal on a car, while tumor suppressor genes are most like the brakes on a car. Oncogenes and tumor suppressor genes are mutated in cancer cells.
Oncogenes are genes overexpressed in cells in which they should not be expressed, thereby leading to cancer.
Some examples of oncogenes are growth factors such as, for example, the  Platelet-derived growth factor (PDGF) or Epidermal growth factor (EGF).
Conversely, tumor suppressor genes are genes that act to regulate cell division and replication, thereby their inactivation also leads to cancer.
A well-known example of a tumor suppressor gene is the p53 gene that acts to control cell division and apoptosis (programmed cell death).
Learn more in:
brainly.com/question/14662375
 
        
             
        
        
        
The answer is surface runoff