<span>Complete the sentence below by selecting the correct words from the drop-down menus.
There are three requirements for natural selection. The requirements are </span><span>✔ variationsimilarity</span><span>, <span>underpopulation✔ overpopulation</span><span>, and <span>✔ adaptationextinction</span><span>.</span></span></span>
Answer:
either helpfu, harmful or neutral
Answer: The correct answer is -
D) giraffes having increasingly longer necks over time.
Natural selection is an evolutionary mechanism that was proposed by Darwin.
According to this mechanism, organisms that are better capable of adapting to their changing environmental conditions, survive and increase their number through reproduction whereas other are eliminated from the population.
Example - Long neck of Giraffe, which is much elongated, lofty stature, that was beautifully adapted for browsing on the higher tree branches. This was an adaptation with slow and gradual change in the gene frequency as the lower vegetation was eaten by other animals. Due to this, giraffes had to search for other source (that was higher tree branches).
This is considered as a peculiar example of natural selection.
Answer:
The offsprings of this punnet square will be Dd, Dd, dd and dd in a ratio 1Dd : 1dd
See attached image for punnet square completion
Explanation:
This question involves a cross involving a single gene with alleles D and d where allele D is dominant over allele d i.e. D will mask the phenotypic expression of d in a heterozygous state.
This cross is between a heterozygous parent (Dd) and a homozygous recessive parent (dd). Parent Dd will produce gametes D and d while parent dd will produce gametes d and d.
Using these gametes in a punnet square, four possible offsprings with two distinct genotypes will be produced. The genotypes are: Dd and dd in a ratio 1:1
Hence, the possibility of having a heterozygous dominant offspring is 1/2 while the possibility of having a homozygous recessive offspring is also 1/2.
Hurricane Katrina.
It was the year 2005 when Hurricane Katrina marked its destruction in United States. The damaged caused by this was beyond repairable, there’s a reason why Katrina is marked as one of the most destructive hurricanes of all times in the history of U.S.
The impact hurricane Katrina had on aquatic ecosystem was terrifying. 150,000 acres of coastal wetlands was damaged. Approximately fifty sea turtles nests were lost. Oil, chemicals, and various other hazardous waste which released in the aquatic ecosystem resulted in the death of aquatic habitats. These are just a few examples of the impact the disastrous Katrina Hurricane had in our ecosystem.
