Explain why scientists believe the universe will continue to expand forever, and describe one piece of evidence that supports the idea that the universe began from a single point.

The universe is currently expanding, as shown by the red‑shift of galaxies.
If the mass density of the universe is below the critical value, the gravitational pull is too weak to halt the expansion, so it will continue forever.
The presence of dark energy further accelerates the expansion, making an eternal expansion even more likely.
A key piece of evidence for a single‑point origin is the cosmic microwave background (CMB) radiation, which is detected uniformly across the sky.
The CMB is the remnant heat/energy from the Big Bang, indicating the universe began from a very hot, dense point.