What component of the cell wall helps in growth and development, as well as keeping it strong to defend itself?

~Lignin

~Pectin

~Cellulose

~Steroids

Two carts, one of mass 2m and one of mass m, approach each other with the same speed, v. when the carts collide, they hook together. assume that positive momentum is to the right. which graph best represents the momentum of both carts over time, before and after the collision?

What was the approximate temperature of the universe at an age of 1015 s?

Kinetic energy depends a. mass b. speed (velocity) c. both of the above d. none of the above