Because natural selection can only increase or decrease frequency of alleles that already exist in the population
I believe choice C is the correct answer
Answer:
True.
Explanation:
The cytoskeleton is also known as the cell skeleton that helps in the movement of the cell organelles. Three different types of cytoskeleton are microtubules, microfilaments and intermediate filaments.
The microtubules shows different function in different cell stages. During prophase stage of the cell cycle, the microtubules gets increase in length. During anaphase stage of the cell cycle , the nonkinetochore microtubules increase in the length the kinetochore microtubules gets short. During telophase stage of the cell cycle, the nonkinetochore microtubules gets disassemble.
Thus, the answer is true.
Answer:
The cell membrane is semi-permeable. It allows some molecules to enter easily inside the cell whereas some molecules are blocked from entering the cell.
Small, polar molecules and hydrophobic molecules enter easily through the cell membrane. But large molecules and ions cannot easily move inside the cell membrane.
A hydrophilic substance like the substance L mentioned in the question enters the cell membrane through the help of carrier proteins. The substance attached to the large protein might enter through active or passive diffusion but it can only enter the cell by attaching to carrier proteins.
The theory was that physical changes in organisms during their lifetime such as greater development of an organ or part through increased use could be transmitted to their offspring.
