How many of the following are avian characters?

A. Endoskeleton is fully ossified

B. Respiration is by lungs

C. Forelimbs are modified into wings

D. Heart is incompletely four-chambered

E. Cold-blooded animals

F. External fertilisation

G. Oviparity

H. Indirect development

The following are the general characters of birds;

• Forelimbs are modified into wings
• Endoskeleton is fully ossified (bony)
• Heart is completely four-chambered
• Warm-blooded (homeotherms) animals
• Respiration is by lungs
• Fertilisation is internal
• Oviparous animals
• Development is direct