Final answer:
In species IV with 2n = 12, a tetrasomic individual would have 14 chromosomes. Offspring with 2n+1 chromosomes are more likely to survive when compared to offspring with 2n-1 chromosomes. In a population with four alleles for a gene, there would be 10 possible genotypes.
Step-by-step explanation:
The question is related to the concept of aneuploidy and chromosome number in tetrasomic individuals of a species. A tetrasomic individual has four copies of a particular chromosome instead of the usual two. If species IV has a normal diploid chromosome number of 2n = 12, this means there are 6 pairs of chromosomes in a normal diploid individual. In a tetrasomic individual for one chromosome, there will be an additional two chromosomes present for one chromosome pair. Therefore, the total number of chromosomes in a tetrasomic individual of species IV would be 12 + 2 = 14 chromosomes.
The most likely to survive between offspring with 2n+1 chromosomes and offspring with 2n-1 chromosomes depends on various factors, but generally, offspring with 2n+1 chromosomes (an example of aneuploidy) have a greater chance of survival in comparison to 2n-1.
If a species has a gene with four alleles circulating, the number of possible genotypes can be calculated using the formula n(n+1)/2 where n is the number of different alleles. For four alleles, there are 4(4+1)/2 = 10 possible genotypes.