Question

which statement about tissues is correct?
tissues are microscopic, and invisible to the naked eye.
tissues are always in the form of sheets of cells.
an organ combines several different tissues.
all the organs of an organ system are composed of a single tissue type.
a tissue is composed of a single type of cell.

Explanation:

• Analyze each option:
• Option 1: Some tissues (e.g., muscle tissue in a large muscle) can be visible to the naked eye, so this is incorrect.
• Option 2: Tissues can have various structures, not just sheets (e.g., connective tissue with scattered cells), so incorrect.
• Option 3: By definition, an organ is a structure made of several different tissues working together (e.g., the heart has muscle, connective, and epithelial tissues), so this is correct.
• Option 4: Organs in a system have multiple tissue types (e.g., digestive system organs have epithelial, muscle, connective, etc.), so incorrect.
• Option 5: Tissues can have multiple cell types (e.g., connective tissue has fibroblasts, macrophages, etc.), so incorrect.

Answer:

C. An organ combines several different tissues.