Earth's history. In the worst one, 250 million years ago, 96 percent of marine species and 70 percent of land species died off. It took millions of years to recover.
The correct answer is a nutrient runoff.
Nutrient runoff is a major reason for eutrophication of surface waters, in which extra amount of nutrients, generally phosphorus or nitrogen, instigate growth of algae. Sources of nutrient pollution involve surface runoff from pastures and farm fields, emissions from combustion, and discharges from septic tanks.
Answer:
C) Books about the lives of inventors, explorers, and artists.
Explanation:
A biography is a book about a person's life that was written by somebody else. Option C) Books about the lives of inventors, explorers, and artists best fits this description. Therefore books in the biography genre would include books about the lives of inventors, explorers, and artists.
Answer:
The correct answer would be 10.
The cell cycle can be divided into four phases namely gap 1 (G₁) phase , synthesis (S) phase, gap 2 (G₂) phase, and mitosis (M) phase.
DNA (deoxyribonuceic acid) content is only replicated and doubled in the S phase. However, the chromosome number remains the same. It can be explained as the number of chromosomes remains the same (2n) but number of chromatids doubles (4n) after S phase.
The number of chromatids restores to 2n in daughter cells after completion of mitosis.
Hence, if number of chromatids in metaphase was 20 i.e. 4n then the number of chromosomes (2n) would be 10.
Hence, 10 chromosomes or 5 pairs of chromosome would be present in the cell during its G₁ phase.