Select all of the answers that apply. which of the following are warning signs that a volcano will soon erupt? 1) animals begin to act weird 2) the sky darkens 3) smoke coming out of the top of it 4) the ground swells or vibrates 5) water level and water temperature increase

The correct answers are:  

3) Smoke coming out of the top of it

When a volcano starts erupting there is a mix of mostly water, carbon dioxide, and sulfur gases that come out from it; this is called "smoke"

4) The ground swells or vibrates

Before an eruption, a material called "magma" moves beneath the volcano to a zone called a "magma chamber"; these movements create seismic vibrations and ground swelling.

Although there is an increased emission of heat and gas from the volcano, the temperature of the water may not be an assured sign of an eruption.

the answer is "a.) well–developed vascular system."

explanation: