What are examples of rigorous course work?

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?

Why do you need to classify the size of a particle

Tortoise shells and snail shells are similar in function: they protect the organism from predators. based on a comparison of the organisms in the images, what can you conclude? 1. tortoises and snails have homologous organs, and they’re evolutionarily related. 2. tortoises and snails have homologous organs, and they belong to same species. 3. tortoises and snails have analogous organs, and they belong to the same species. 4. tortoises and snails have analogous organs, and they don’t belong to the same species. 5. tortoises and snails have analogous organs, and they aren’t evolutionarily related.