The members of class Aves are characterized by the presence of

Options

A. Hollow jaws and four chambered heart
B. Bipedal locomotion and body covered with feathers
C. Two chambered heart with ossified skelecton
D. Homoiothermic condition and viviparity

Answer

**Step-by-Step Solution:**

1. **Understanding Class Aves**: The class Aves consists of birds, which are warm-blooded vertebrates characterized by certain unique features.

2. **Identifying Key Characteristics**:
- **Hollow Bones**: Birds have a lightweight skeletal structure that includes hollow bones, aiding in flight. However, this option mentions "hollow jaws," which is incorrect as birds do not have jaws but beaks.
- **Bipedal Locomotion**: Birds typically move using two legs (bipedal locomotion). Their forelimbs are modified into wings, which assist in flight.
- **Body Covered by Feathers**: Feathers are a distinctive feature of birds, providing insulation and aiding in flight.
- **Heart Structure**: Birds possess a four-chambered heart, which is efficient for their high metabolic rates.
- **Reproductive Method**: Birds are oviparous, meaning they lay eggs rather than giving live birth (viviparity).

3. **Evaluating the Options**:
- The first option is incorrect due to the mention of "hollow jaws."
- The second option correctly states "bipedal locomotion and body covered by feathers," which are key characteristics of birds.
- The third option incorrectly states "two-chambered heart," as birds have a four-chambered heart.
- The fourth option incorrectly states "viviparity," as birds lay eggs.

4. **Conclusion**: The correct answer is the second option, which highlights the bipedal locomotion and the body covered by feathers as defining characteristics of the class Aves.

**Final Answer**: The members of class Aves are characterized by the presence of bipedal locomotion and a body covered by feathers.

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