Q: What kind of muscle cells undergo twitch-type contractions with long refractory periods followed by brief relaxation periods, allowing the heart to fill with blood for the next cycle? Choices: - nervous muscle - skeletal muscle - smooth muscle - cardiac muscle A:
cardiac muscle

Q: When electrons return to a lower energy level, they emit the excess energy in the form of what? Choices: - weight - electricity - energy - light A:
light

Q: What is the name for the organs behind the head of a fish that absorb oxygen from water? Choices: - pores - alveoli - lungs - gills A:
gills