Q: Q: What is the membrane that surrounds a fetus called? A: | OPTIONS:
- cell membrane
- umbilicus
- umbilical sac
- amniotic sac
A: amniotic sac

Q: Q: What is the critical factor for the survival of segmented worms? A: | OPTIONS:
- sunlight and water
- humidity and sunlight
- sunlight and warmth
- water and humidity
A: water and humidity

Q: Q: The three types of mammals are characterized by their method of what? A: | OPTIONS:
- specializaiton
- differentiation
- pattern
- reproduction
A: reproduction

Q: Q: What type of energy of a system is the sum of the kinetic and potential energies of its atoms and molecules? A: | OPTIONS:
- external energy u
- primary energy u
- deep energy u
- internal energy u
A: internal energy u