Answer:
An index fossil is also known as guide fossils or indicator fossil. They are fossils used to determine and identify geologic periods.
The main characteristics of an index fossil include :
1.It must be distinctive.
2.It must be widespread.
3. It must be abundant
4. It must be limited in geologic time.
Due to trends and studies of most fossil-bearing rocks being formed in the ocean, the major index fossils are mostly marine animal or plant organisms.
Answer:
Aquaculture is a type of farming performed in water bodies like lakes, ponds, oceans to breed aquatic plants and animals like fish, mollusks, crustaceans, algae, etc. Aquafarming is done to increase food production and to earn money from it.
Apart from the advantages aqua farming has several disadvantages. One of the main disadvantages is the transfer of parasites or diseases from one fish to another is easy in aquaculture because fishes live in dense populations in aquaculture. So fish in aquaculture are highly vulnerable to diseases.
Excess fecal matter produced by farmed fish can pollute the ecosystem which has an adverse effect on the other species live in that ecosystem.
There ar 5 in nitrogen, 20 in hydrogen, and 5 in chlorine. In all that’s 30 compounds.
Cancer<span> can </span>start<span> when just one of them </span>begins<span> to grow and multiply too much. The result is a growth called a tumor. Benign tumors are localized growths - they only cause problems if they put pressure on nearby tissues, such as the brain.</span><span />