When does osteogenesis begin? *When a fetus is 13-15 weeks old
When a baby is born
When a fetus is 32 weeks old
When a child is 2 years old

Which group of chordates does  notpossess true backbones?                 a.  birds      b.  frogs and toads      c.  lampreys      d.  crocodilians

Which of the following is the best definition of aerobic respiration? o a. the cellular process that releases energy by breaking down glucose o b. physical activity that involves the repeated motion of large muscle groups o c. physical activity that increases heart rate and breathing rate o d. the cellular process that converts solar energy to chemical energy

An example of internal feedback working to maintain homeostasis is your a. decreased respiration rate when you are studying b. decreased heart rate when you are sad c. increased respiration rate when your muscles need more oxygen d. increased heart rate when your lungs need more oxygen