input: OPTIONS:
- produce off
- Roll over.
- develop off
- reflect off Now, answer this question: Answer the following question given this paragraph: Waves may reflect off an obstacle that they are unable to pass through. When waves are reflected straight back from an obstacle, the reflected waves interfere with the original waves and create standing waves . These are waves that appear to be standing still. Standing waves occur because of a combination of constructive and destructive interference. You can see animations of standing waves at the URLs below. Q: What do waves do when they are unable to pass through an object? A:
A:
output: reflect off

Answer the following question given this paragraph: Examples of protozoa include amoebas and paramecia. Q: Amoebas and paramecia are examples of what? A:

OPTIONS:
- vertebrates
- bacteria
- protists
- protozoa

Answer: protozoa

Problem: OPTIONS:
- liver
- brain
- lungs
- skin
Q: Answer the following question given this paragraph: The epidermis is the outer layer of skin. It consists almost entirely of epithelial cells. There are no blood vessels, nerve endings, or glands in this skin layer. Nonetheless, this layer of skin is very active. It is constantly being renewed. How does this happen?. Q: Lacking blood vessels, nerve endings, or glands, the epidermis is the outer layer of what? A:
Answer: skin

Problem:OPTIONS:
- pus
- Blood
- progesterone
- sebum

Answer the following question given this paragraph: Sebaceous glands produce an oily substance called sebum. Sebum is secreted into hair follicles and makes its way to the skin surface. It waterproofs the hair and skin and helps prevent them from drying out. Sebum also has antibacterial properties, so it inhibits the growth of microorganisms on the skin. Q: What kind of oily substance is secreted from sebaceous glands? A:
****
A: sebum

Answer the following question given this paragraph: Hydrocarbons are extremely important to modern life. Their most important use is as fuels. Hydrocarbons are also used to manufacture many products including plastics. The main source of hydrocarbons is fossil fuels. Q: What is the main source of hydrocarbons? A:
OPTIONS:
- photosynthesis
- greenhouse gases
- decomposers
- fossil fuels
fossil fuels

Answer the following question given this paragraph: The speed of a wave is a product of its wavelength and frequency. Because the speed of electromagnetic waves through space is constant, the wavelength or frequency of an electromagnetic wave can be calculated if the other value is known. Q: The speed of a wave is a product of its wavelength and what else? A:
OPTIONS:
- voltage
- density
- magnitude
- frequency

Answer:
frequency