Question

Which of these are not present in birds

• A. Bones
• B. Muscles
• C. Kidneys
• D. Teeth

Answer 1

The correct option is D Teeth

• Some flightless birds like penguins have only solid bones. The skull bones have air cavities that are continuous with the nasal cavities. Trunk bones include the vertebrae, breastbone and pelvic bones – also contain air sacs invading from the lungs. These are all called pneumatic bones.
• Birds have muscles as well. The largest muscles in the bird are the pectorals or the pectoralis major, which control the wings and makeup about 15–25% of a flighted bird's body weight.
• A bird has paired kidneys which are connected to the lower gastrointestinal tract through the ureters. Unique to birds is the presence of two different types of nephrons (the functional unit of the kidney) - both reptilian-like nephrons located in the cortex and mammalian-like nephrons located in the medulla.
  
• Birds do not have teeth but have curved beaks and a hearty digestive tract that help them grind and process food.

So, the correct answer is 'Teeth'.