Are the ultimate cause of alleles. a. mutations b. karyotypes c. dna molecules d.

Option A, Mutation

Explanation:

Mutation can cause the variation in a defined genetic set of an organism there by producing allele of varied types. However an allele is a variant gene. For example

A male flower has following allele – WW (representing dominant white color flower)

A female flower has following allele – ww (representing recessive blue color flower)

If these two flower mutate either through natural processes or though the mating, new species of flower with a different and unique genotype (allele set) is formed

for example a grey color flower with unique allele set - Ww

Alleles are carried on chromosome which expresses certain trait, variation in genotype also brings variation in allele's trait expression.

Hence, option A is correct

Male fiddler crabs tread an evolutionary fine line between growing an enlarged claw better for signalling to females or one better for fighting. ... The males use their small claw for feeding and the large one to attract females for mating, threaten other males and as a weapon when fighting.another example of this rams the males have large racks while the female do not

Explanation: