Answer:
Earth's tilted axis causes the seasons. Throughout the year, different parts of Earth receive the Sun's most direct rays. So, when the North Pole tilts toward the Sun, it's summer in the Northern Hemisphere. And when the South Pole tilts toward the Sun, it's winter in the Northern Hemisphere
Explanation:
Meiosis is involved in the formation of the gametes of multicellular organisms.
<h3>How do multicellular organisms reproduce?</h3>
Both plants and animals reproduce by developing new individuals, through gametes or reproductive cells.
<h3>Characteristics of multicellular organisms reproduction</h3>
- Many multicellular organisms always arise from a single cell called a zygote, the result of the union of two gametes (female and male).
- The zygote subdivides rapidly throughout gestation, forming the entire body of the creature that, from its birth, begins to grow.
Therefore, multicellular organisms reproduce by means of certain types of reproductive cells that are generated and take care of building a complete new individual.
Learn more about multicellular organisms reproduction here: brainly.com/question/220315
It is definitely not a primary source: this would be a book itself.
Now, is it a tertiary source? I don't think so: the author of the review should have read the book and should only be referring to this book in the review.
I think it's a secondary source.
Question: Does geographic distance between salamander populations increase their reproductive isolation? To answer this question, researchers studied populations of the dusky salamander (Desmognathus ochrophaeus) living on different mountain ranges in the southern Appalachian Mountains. The researchers tested the reproductive isolation of pairs of salamander populations by leaving one male and one female together and later checking the females for the presence of sperm. Four mating combinations were tested for each pair of populations (A and B)—two within the same population (female A with male A and female B with male B) and two between populations (female A with male B and female B with male A). The proportion of successful matings for each mating combination was measured. For example, when all the matings of a particular combination were successful, the researchers gave it a value of 1; when none of the matings were successful, they gave it a value of 0. Then the researchers calculated an index of reproductive isolation that ranged from 0 (no isolation) to 2 (full isolation). The reproductive isolation value for two populations is the sum of the proportion of successful matings of each type within populations (AA + BB) minus the sum of the proportion of successful matings of each type between populations (AB + BA).
The table (Figure 1) provides data for the geographic distances and reproductive isolation values for 27 pairs of dusky salamander populations.
Part A - Understanding experimental design
What hypothesis did the researchers test in this study?
Answer:
"Reproductive isolation increases with geographic distance between dusky salamander populations"
Explanation:
The mechanisms of reproductive isolation are a assemblage of evolutionary mechanisms, behaviors and physiological procedures dangerous for speciation. They avert followers of dissimilar types from manufacturing offspring, or confirm that any offspring are germ-free. While in allopatric speciation the reproductive isolation is resolute superficially by the spatial isolation of populations, during sympatric speciation specific groups of persons create distinct mating organizations with self-like persons while distribution the similar home with the rest of the unique inhabitants.
