Correct Answer: B. crop rotation

Correct Answer: D. Genotype

Correct Answer: B. at the same logus of a homologous chromosome

Correct Answer: D. serving as a growth regulator

Correct Answer: B. fish

Correct Answer: B. The number present in a specie is constant

Correct Answer: B. is light and easy to dig

Correct Answer: A) competition

Explanation

The question is asking which biological association directly contributes to succession in a community. In simple terms, succession refers to how an ecosystem changes over time. The options given are competition, predation, parasitism, and commensalism. Competition is when two or more organisms compete for the same resources, such as food or territory. This can lead to the survival of the most adapted organism, but it does not directly contribute to succession. Predation is when one organism feeds on another organism. While it can have an impact on the size and distribution of populations, it also does not directly contribute to succession. Parasitism is a relationship in which one organism benefits at the expense of the other organism. While it can have an impact on the health of populations, it also does not directly contribute to succession. Commensalism is a relationship in which one organism benefits without affecting the other organism. This also does not directly contribute to succession. Therefore, the correct answer is option A, competition, as it can lead to the survival of the most adapted organism, which can then contribute to the succession of the ecosystem. It is important to note that succession is a complex process that involves multiple factors, including abiotic and biotic factors, and can take a long time to occur. To learn more about this, please read the relevant sections of the recommended textbooks.

Correct Answer: A) two identical copies of a single chromosome produced during s-phase

Explanation

This question is asking about sister chromatids. Sister chromatids are two identical copies of a single chromosome that are produced during the S-phase of the cell cycle. During this phase, the DNA in the cell is replicated, resulting in two identical copies of each chromosome. These two copies are called sister chromatids. Option A is the correct answer because it accurately describes sister chromatids. Option B is incorrect because pairs of chromosomes refer to homologous chromosomes, which are not identical. Option C is incorrect because the points of attachment of centromeres to the chromosomes are called kinetochores. Option D is also incorrect because chromosomes found in cells of sisters is not a scientific term. It is important to understand the structure of chromosomes and their duplication during the cell cycle. This knowledge is important in understanding genetics and inheritance. To learn more about this, please read the relevant sections of the recommended textbooks

Correct Answer: B) permeability of membrane

Explanation

The question is asking about how substances move across the cell membrane and which factor controls this movement. The options provide different factors that could affect substance movement, and we need to choose the correct one. The cell membrane is a thin layer of molecules that surrounds the cell and separates the inside from the outside. It is a selectively permeable membrane, which means that it allows some substances to pass through while blocking others. The movement of substances across the cell membrane is crucial for the cell to function properly. The options given are the size of permeating particle, permeability of membrane, membrane proteins, size of permeating particle and membrane proteins, and all. The size of the particle and the presence of membrane proteins can affect substance movement, but the correct answer is the permeability of the membrane. Permeability refers to how easily a substance can pass through the membrane. A highly permeable membrane allows many substances to pass through, while a low permeability membrane restricts movement. The permeability of the cell membrane is controlled by the structure and composition of the membrane itself. In summary, the correct answer to the question is option B: permeability of membrane. This means that the ease with which substances pass through the cell membrane is determined by the permeability of the membrane. To learn more about this, please read the relevant sections of the recommended textbooks.