Layers of rock that bend can produce a downward fold known as a(n)

Syncline

Explanation:

Synclines are the down folds that are constructed due to the compressive forces acting on a layer from both sides. It usually occurs in size ranging from a microscopic scale to a large megascopic scale. The oldest rocks are present at its outermost limb and the rocks become gradually younger toward its hinge area.

In an outcrop, the syncline and the anticline, both form simultaneously. The limbs that dip towards the trough of the fold indicate a syncline whereas the limbs that dips towards the crest are the anticline. The variation in the shape of these foldings (anticline and syncline) depends upon the intensity of the force.

out of these options:

ability to burn paper

pure sodium reacting violently with water

the boiling point of water

helium does not tend to react with anything

i would say this is a physical property:

helium does not tend to react with anything

why? :

i said helium does not tend to react with anything because well, it reacts to ! but ability to burn paper, pure sodium reacting violently with water, & the boiling point of water are chemical or

physical properties: the properties of a substance that can be observed without changing the chemical makeup of the substance

chemical properties: properties of a substance relating to the chemical nature and reactivity of the substance