*Question*
Rain causes erosion, and soil Erosion Soil erosion is what happens when soil is washed or blown away. Given these facts, what causes soil to be washed or blown away among the following options: - Roads - rivers - wind - shoveling - clouds - storms - rain - combustion
**Answer**
rain

*Question*
Immunodeficiency occurs when the immune system is not working properly, and people with healthy immune systems usually get well on their own. Given these facts, what does immunodeficiency do among the following options: - enormous damage to homes - Make money - major threat to health - harm them - Plant growth is reduced - Stay sick shorter - Stay sick longer - Get well faster
**Answer**
Stay sick longer

*Question*
Adult sponges produce eggs and sperm, and sponges are the most primitive multicellular animals. Given these facts, the most primitive multi-cellular animals produce what among the following options: - Electrical energy - eggs and sperm - harmful substances - scarce resources - Organic compounds - Chemical energy - fur and fat - aerobic capacity
**Answer**
eggs and sperm

*Question*
Hair is a fiber that is found only in mammals, and bats have hair like all mammals so they can stay warm. Given these facts, what keeps mammals warm among the following options: - fibers - eyeballs - white blood cells - fur - the skin - sweating - nostrils - heat
**Answer**
fibers