The diagrams below show a cross-section of an environment in which there are no earthworms present and a cross-section of an env
ironment in which earthworms are present.Which of the following statements are true of how earthworms affect their environment according to these diagrams?
I. Earthworms increase plant yields.
II. Earthworms decrease the quantity of topsoil.
III. Earthworms are beneficial to their environments.
IV. Earthworms are detrimental to their environments.
A.
I, II, and IV only
B.
II and IV only
C.
I, II, and III only
D.
I and III only
I. Earthworms increase plant yields.
II. Earthworms decrease the quantity of topsoil.
III. Earthworms are beneficial to their environments.
IV. Earthworms are detrimental to their environments.
A.
I, II, and IV only
B.
II and IV only
C.
I, II, and III only
D.
I and III only
1 answer:
You might be interested in
Answer:
The parent's genotypes are:
Ddpp - tall, white parent
ddPp - dwarf, purple parent.
Explanation:
This question involves two different genes coding for height and flower color in pea plants. The alleles for tallness (D) and purple color (P) are dominant over the alleles for dwarfness (d) and white color (p) respectively.
According to this question, a tall plant with white flowers is crossed with a dwarf plant with purple flowers to produce the following proportion of offsprings: 1/4 tall purple, 1/4 tall white, 1/4 dwarf purple, and 1/4 dwarf white.
Since some of the offsprings contain recessive alleles for both or either genes, the dominant traits of the parent is controlled by an heterozygous genotype. This means that the tall plant with white flowers has a genotype: Ddpp while the dwarf plant with purple flowers has the genotype: ddPp. In a cross between Ddpp × ddPp, 1/4 of each combination of alleles is produced in the offsprings (see punnet square in the attachment).
