Solution:
A liver fluke is a parasitic worm. Infections in humans usually occur after eating contaminated raw or undercooked freshwater fish or watercress. After liver flukes have been ingested, they travel from your intestines to your bile ducts in your liver where they then live and grow.
Hence D is the correct answer.
Solution:
The cell membrane, also known as the plasma membrane, is a semi-permeable membrane that surrounds the cell and separates its internal environment from the external environment. It regulates the passage of substances into and out of the cell. The term "semi-permeable" means that while some substances can freely pass through the membrane, others are restricted or selectively allowed based on their size, charge, and other properties. The cell membrane is crucial for maintaining the cell's internal environment and facilitating various cellular processes such as nutrient uptake, waste removal, and cell communication.
Option A: Cell membrane is the correct choice because it is synonymous with the plasma membrane, which is semi-permeable.
Option B: Plasma membrane is another term for the cell membrane and is indeed semi-permeable.
Option C: Cell wall is a rigid structure found in plant cells, fungi, and some bacteria. Unlike the cell membrane, the cell wall is not semi-permeable; it provides structural support and protection to the cell.
Option D: Nucleus is a membrane-bound organelle that contains the cell's genetic material. It is not semi-permeable; its membrane, known as the nuclear envelope, has pores that regulate the passage of molecules, but it is not considered semi-permeable in the same sense as the cell membrane.
168. When a Cuttlefish is described as a Molluscs, it is at which level of classification?
