*Question*
Oxygen is just one substance transported by the blood, and active brains and muscles require more oxygen and nutrients. Given these facts, muscles require substances transported in the body by among the following options: - sugar - food - fibers - fat - neurons - blood - glucose - bones
**Answer**
blood

*Question*
Disease-causing microbes have a negative impact on the body, and pathogens are microbes that cause disease. Given these facts, what has a negative impact on the body among the following options: - pathogens - medicines - antibiotics - smallpox - amoebae - viruses - smoking - antibodies
**Answer**
pathogens

*Question*
Adrought can change the color of an environment from green to brown, and due to the drought, there is no water. Given these facts, what can change the color of an environment from green to brown among the following options: - the ocean - a lack of water - rain - harmful substances - sleet - deforestation - Greenhouse gases - Greenhouse gasses
**Answer**
a lack of water

*Question*
The looseness of soil has a positive impact on a plant 's roots' growth in that soil, and to improve soil, add several top-dressings of dirt or compost. Given these facts, what has a positive impact on a plant's roots' growth among the following options: - reducing acid rain - color of dirt - looseness of dirt or compost - basic building blocks of life - biological diversity - lead in the soil - Evaporation of water - a lack of soil
**Answer**
looseness of dirt or compost