More than a million years ago the continent of africa hit north america

To solve the system of equations below, pedro isolated the variable y in the first equation and then substituted it into the second equation. what was the resulting equation? { 5y=10x {x^2+y^2=36

Aflower has 26 chromosomes. to create a new flower, how many chromosomes would a sperm cell have? what is this process called? part 2: within a flower cell that has 26 chromosomes, how many chromosomes would a cell that is created within the stem of a flower as it grows, have? what is this process called?

You are standing next to a really big circular lake. you want to measure the diameter of the lake, but you don't want to have to swim across with a measuring tape! you decide to walk around the perimeter of the lake and measure its circumference, and find that it's 400\pi\text{ m}400? m. what is the diameter dd of the lake?