How did internal political strife make protecting the roman empire difficult?

The distance d that a car can travel in a certain amount of time t can be found by multiplying the rate of speed r by the travel time. if a car has already travel 4 miles, the formula for the total distance travel is d= rt + 4. which of the following gives the value of r, in terms of d and t?

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.

Which key skills does the sat writing and language section asses?