What causes a sound wave to echo in an empty house? A. Transmission of waves from a person speaking
B. Reflection of waves off smooth walls
C. Refraction of waves by a person speaking
D. Absorption of waves by rough walls

Chloroplasts and bacteria are in size. a. similar b. at different ends of the size range c. exactly the same d. none of these

Which of the following was not a major animal on land during the carboniferous period? amphibians insects both a and b none of the above

The table above shows five different types of chromosomal abnormalities that can occur during meiosis. they result in either an individual having too many or too few chromosomes in their genome. what is the most likely cause of these chromosomal abnormalities?