Final answer:
Perennial ryegrass does not have greater low-temperature hardiness than Kentucky bluegrass, making the statement false. Mosses thrive in the Arctic tundra due to their ability to grow without true roots on hard surfaces.
Step-by-step explanation:
The statement 'Perennial ryegrass has greater low-temperature hardiness than Kentucky bluegrass' is false. Kentucky bluegrass is known for its ability to withstand colder temperatures and is commonly used in climates that experience harsh winters due to its low-temperature hardiness. Perennial ryegrass, while a popular grass for lawns and athletic fields due to its quick germination and establishment, does not have the same level of hardiness in low temperatures as Kentucky bluegrass.
Regarding the growth of mosses in the Arctic tundra, the correct answer is they do not have true roots and can grow on hard surfaces. This characteristic allows mosses to survive in the tough conditions of the Arctic tundra, where the soil can be too hard for many plants with deeper root systems to penetrate.