Which of these statements expresses a scientific theory? A. The leaves of all plants consist of several kinds of cells.
B. Cells that lack a nucleus are usually smaller than cells with a
nucleus.
C. An unidentified material that consists of cells must be from a
living organism
D. The cell is the basic structural and functional unit of living
organisms

The correct answer is C.

Explanation:

An unidentified material that consists of cells must be from a

living organism.

It sounds more like an theory.

hello there,

guys i’m confused.

which rock will weather faster?

answer: b rock

before, trains worked using the steam engine. thus, it uses heat so it is crucial to apply heat balance. the steam engine absorbs energy during the stage of boiling water. so, this is the endothermic reaction. when the steam is used to work the piston, it has to release this energy through running the train. the excess energy is released as an exhaust to the chimney. this is the exothermic process because it releases energy to the surroundings.