Tundra has mostly mosses, lichens, and grasses. What abiotic factors prevent other vegetation from growing in this biome?

Y’all i need answers plss people are saying me and my brother look alike although we’re two different ages. one year apart i’m a girl, btw i’m thinking we could be fraternal twins idk my parents and my friends think we look alike

Nasa scientists must work together to make sure that everything is correct and accounted for when launching a shuttle. besides a physicist, what other type of scientist would be in making sure that the shuttle has the appropriate type and amount of fuel to reach its destination?

If 360 joules of work are needed to move and create a distance of 4 m what is the weight of the crate