Are the people on brainy dumb at Khan Academy Answers?

Ascientist wants to find the radius in meters of his hemispherical dome he found that the surface area of the entire sphere containing the dome is 682 square meters which equation could he use to find the domes radius

Afood web shows who eats who in any given habitat. every living thing, from one-celled algae to giant blue whales, needs food to survive. each food web is a possible pathway that energy and matter can follow through the habitat. a food web begins with producers: organisms that convert sunlight into usable chemical energy. the food web is completed by the decomposers who turn organic wastes, such as decaying plants, into inorganic materials, such as nutrient-rich soil. decomposers complete the cycle of life, returning nutrients to the soil or oceans for use by producers. in this food web, identify the decomposer.

All of the following are examples of service-learning opportunities except: a. donating time to senior citizen war veterans and writing a report about the experience for your u. s. history class. b. getting a part-time job at a habitat restoration center. c. reading to second-grade students as part of your assigned reading time for your english class. d. planting trees in your community and then discussing global warming in your science class.