1) “Melopsittacus undulatus” (leia-se os dois nomes em itálico), conhecido popularmente como periquito-australiano, pode apresentar plumagem nas cores azul, amarela, branca e verde. Essa característica é condicionada por dois pares de genes, com segregação independente, que têm interação entre si. A cor branca é condicionada por genes homozigotos recessivos. Indivíduos que apresentam em ambos os Ioci pelo menos um dos alelos dominantes são verdes. Quando apresentam um um Ioci com genes recessivos e o outro com, pelo menos, um alelo dominante, são azuis ou amarelo. Do cruzamento de dois indivíduos duplamente heterozigotos, espera-se encontrar:

It is expected to observe individuals exhibiting green, yellow, blue, and white colors in a phenotypic ratio of 9:3:3:1, respectively.

Explanation:

This example is a classic case of a dihybrid cross involving two unlinked genes that differ in the same observed trait. In this case, the genotype double homozygous recessive is white, while the presence of one dominant allele in one of these genes results in individuals with either blue or yellow color. Finally, the presence of two dominant alleles results in individuals with blue color.

Phenotypic and genotypic ratios:

gene 1 two alleles U u

gene 2 two alleles N n

Cross:  

UuNn x UuNn

uunn: white color (1/16)

U_nn: yellow color (3/16)

uuN_: blue color (3/16)

U_N_: green color (9/16)

stress fractures occur largely in the feet and legs and are common in sports that require repetitive impact, primarily running/jumping sports such as gymnastics or track and field.

the earth is thought to have been formed about 4.6 billion years ago by collisions from a cloud of hydrogen, helium, rock, ice and other materials. these were pulled together by gravity to form objects in and around earth like- asteroids and small early planets called planetesimals.

so, the best possible answer to this question will be option d- to harden materials to form different parts of earth’s layers