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>
Answer:
Helium
Explanation:
Helium is extracted in a few places in the world, namely USA, Algeria, Russia and Qatar. Helium is abundant in space, where it's produced as a product of the fusion reaction inside stars such as the sun.
Answer:
Robert Hazen’s studied enviromental and biological processes that might have been critical for life, and also for the formation of approximately two-thirds of Earth's mineral species (see Hazen et al., 2008; Gonzalez & Richards 2020)
.
Explanation:
Hazen provided evidence about how first organic molecules were generated on the primitive earth millions of years ago. He observed that high-pressure hydrothermal vents may provide food for underwater ecosystems. It represents a piece of critical evidence on the origin of life.
You can read these articles that are certainly clarifying in the description of his experiments and discoveries:
1- Hazen, R. M., Papineau, D., Bleeker, W., Downs, R. T., Ferry, J. M., McCoy, T. J., ... & Yang, H. (2008). Mineral evolution. American Mineralogist, 93(11-12), 1693-1720.
2- Gonzalez, G., & Richards, J. W. (2020). The privileged planet: how our place in the cosmos is designed for discovery. Gateway Editions.
It is not it something like sand because it would keep the fossil preserved.
