Question

what is acid??

what are sources of heat??​

Answer 1

Answer:

a liquid substance that can dissolve metal and may burn your skin or clothes. Acids have a pH value of less than 7.

Explanation:

A heat source is anything that can heat up a spacecraft. Heat sources can be external (from outside the spacecraft) or internal (from inside the spacecraft). External heat sources include: the Sun. reflected sunlight from planets and moons.

Answer 2

Answer:

any substance that in water solution tastes sour, changes the colour of certain indicators.