How are electromagnetic waves different from mechanical waves? (2 points) Electromagnetic waves are all high frequency; mechanical waves are all low frequency.
Electromagnetic waves can travel through a vacuum; mechanical waves require a medium.
Electromagnetic waves are visible; mechanical waves are invisible.
Electromagnetic waves always reflect; mechanical waves always refract.

Iknow the answer to 13 is b and 14 is d. i just need to know why the correct answers are correct

Select the correct answer how does the heat content of the reaction change in the process of photosynthesis when a glucose molecule is formed? ca the value of is negative the value of qis positive the value of a remains constant the value of a decreases the value of equals zero e

Rocks, as they are compressed, begin forming mountains above the earth's surface when two continental plates converge. the continental crust increases in depth as the mountains grow above. the himalayan mountains formed at a convergent plate boundary in this manner. the rocks are smashed together causing them to due to the intense heat and pressure from the colliding plates and eventually forming rock. a) melt; igneous b) layer; sedimentary c) recrystallize; metamorphic d) melt into the earth's interior; metamorphic