Answer:
1. A pure substance has a definite constant composition.
2. A compound is composed of two or more types of matter that can be present in varying amounts.
3. A solution is a homogeneous mixture.
4. A mixture that is not uniform throughout is a Heterogeneous mixture
5. A pure substance that cannot be broken down chemically is a element.
6. A characteristic of matter that’s not associated with a change in its chemical composition is known as a physical property.
7. Wax melting is an example of a physical change in the state of matter.
8. A banana peel turning brown is an example of a chemical change in the state of matter.
The answer is C. nitrogen.
Plants are main producers in ecosystems so, primary productivity of ecosystems depends on them. Carbon is necessary for plants, but it is widely present in plants. On the other hand, calcium and sodium are not as essential. However, nitrogen is important for plants because it is necessary to make proteins. Proteins take part in many different processes such as photosynthesis (this is actually primary productivity). But, nitrogen is not available to plants, they cannot absorb it simply from the air but rely on some symbiotic bacteria which are able to.
Answer:
Explanation:
How would you classify the relationship between coral and the small crabs? Their relationship is mutualistic, as the crabs provide protection for the coral reef and the reef provides the crabs a home.
They are different in structure as one serves in an open system (lymphatic system) while the other serves is closed system (circulatory system).
They are similar in the concept that they both return fluids back to heart. Lymphatics return lymph while veins brings blood back to heart.
Hope this helps.
