Mammals Incorrect Statement Identification

The question asks to identify the statement that is incorrect regarding mammals.

Analyzing Mammal Characteristics

Let's evaluate each statement:

• Statement 1: Normally mammals have hair. This is generally true. Hair or fur is a characteristic feature of mammals, aiding in insulation, camouflage, and sensory functions.
• Statement 2: Some mammals lay eggs. This is also true. Monotremes, such as the platypus and echidna, are mammals that reproduce by laying eggs.
• Statement 3: Heart is three chambered. This statement is incorrect. All mammals, including humans, possess a four-chambered heart (two atria and two ventricles). This ensures efficient separation of oxygenated and deoxygenated blood, supporting their endothermic (warm-blooded) nature. Amphibians and most reptiles have three-chambered hearts.
• Statement 4: Mammary gland is present to feed young ones. This is a defining characteristic of mammals. Mammary glands produce milk to nourish their offspring.

Conclusion on Incorrect Statement

Based on the analysis, the incorrect statement about mammals is that they have a three-chambered heart. Mammals characteristically have a four-chambered heart.