In flies, red eyes (r) are dominant to brown eyes (r). a heterozygous fly is crossed with homozygous recessive fly.
what percentage of offspring will have brown eyes?

50%  of offspring will have brown eyes

Explanation:

A heterozygous individual will have the genotype Rr while an individual who is homozygous recessive will have the genotype rr. A cross between the two will result in offspring with phenotype Rr and rr in the ratio of 1 : 1. This can be observed from the Punnet square attached.  The same is the case for the phenotype. The ration of brown eyes to red eyes will be approximately 1 : 1

When a virus infects a host cell, it uses the cell's machinery to make copies of its own genetic material in a process called replication. finally, during the process of self-assembly, that protein shell and the copies of the virus's genetic material are assembled into new viruses.

There would be no evaporation so no water cycle