<span>Euglena is eukaryotic, because they have organelles and a nucleus. </span>
His work, which was documented and repeatable, contradicted the accepted cell theory, so a change in the theory was required.
Answer:
D. A bicycle rusting.
Explanation:
A. is incorrect because tearing a piece of paper is a physical change, not a chemical change.
B. is incorrect because we are just heating up the object. That only changes how fast the particles are moving and the change in state of matter.
C. is incorrect because we are adding heat to change a state of matter (from solid to liquid) and it is a physical change.
Therefore, only D. is the correct answer. Iron rusts, and when it does, it chemically changes into an iron oxide (rust).
Answer:
- A, B, C and D are: elements or molecules
- A and B are: reactants
- C and D are: products
Explanation:
The expression "A + B <--> C + D" represents a chemical equation. A chemical equation represents the "mixture" of molecules or elements that will react and form other molecules and elements, so we can say that A, B, C and D represent molecules or elements.
But not only that. In a chemical equation, the elements and molecules that are before the symbol "<-->" represent the reagents in the equation. Therefore, A and B are the reagents. The elements or molecules found after the symbol "<-->" are the products of the reaction. Therefore, C and D are the products.
