The answer is B. Disruptive selection
Yes, species pairs show more than one barrier to reproduction. Examples include damselflies with incompatible reproductive organs, species of flowers attracting different pollinators, bird species with different mating dances, and species producing infertile offspring.
Yes, there are several instances where species pairs show more than one barrier to reproduction. These barriers can be prezygotic or postzygotic. Examples include damselfly males and females of different species that have differently shaped reproductive organs, thus creating a mechanical barrier. This means their body parts simply do not fit together and reproduction cannot occur.
Also, two species of flowers may attract different pollinators, creating a barrier known as habitat isolation, in which the species live in the same area but different habitats. Furthermore, bird species may display different mating dances. This is behavioral isolation where species differ in their mating rituals. There's also reduced hybrid fertility where two species of insects produce infertile offspring. The mechanisms of reproductive barriers in nature are complex and diverse in their operation.
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Answer:
Grana
Explanation:
The thylakoids are arranged in tight stacks called grana (singular granum).
Answer:
A stack of thylakoids is called a grana.
Explanation:
Thylakoids are flattened, membrane-bound structures found within the chloroplasts of plant cells and some photosynthetic bacteria. They contain the pigments and other molecules necessary for the process of photosynthesis.
A grana is formed when multiple thylakoids stack on top of each other. These stacks are connected by intergranal lamellae, which are extensions of thylakoid membranes that link adjacent grana together.
The arrangement of thylakoids into grana is important for the efficiency of photosynthesis. It increases the surface area available for light absorption and provides a structured organization for the flow of electrons and energy during the light-dependent reactions of photosynthesis.
In summary, a stack of thylakoids is called a grana. This organization of thylakoids plays a vital role in the process of photosynthesis by providing an efficient structure for light absorption and electron transport.
There are 46 chromosomes in each cell at metaphase II in meiosis in humans. Normal human body cells each have 46 chromosomes. Prior to meiosis, the DNA replicates and each cell gets 92 chromosomes.
A germ cell in the testis in Metaphase II of Meiosis has 23 chromosomes.
In Metaphase II of Meiosis, the chromosomes line up at the equator of the cell and are ready to be separated into two daughter cells. Each daughter cell will receive half the number of chromosomes as the parent cell. In humans, the diploid number of chromosomes in a somatic cell is 46, while the haploid number of chromosomes in a germ cell is 23.
Therefore, in Metaphase II of Meiosis, a germ cell in the testis would have 23 chromosomes.
Learn more about total chromosomes in a germ cell in metaphase of meiosis ii here:
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