Climate Zones Objectives: 1. Describe Earth's major climate zones. 2. Explain how climate zones are characterized. Notes: According to the three cell convection model of each hemisphere the Earth neatly separates itself into three distinct climate zones; the polar, temperate, and the tropical zones.limate Zones Objectives: 1. Describe Earth's major climate zones. 2. Explain how climate zones are characterized. Notes: According to the three cell convection model of each hemisphere the Earth neatly separates itself into three distinct climate zones; the polar, temperate, and the tropical zones.
The nucleus is a large roundish organelle. It is bounded by a double membrane which has numerous pores. Inside the nucleus are chromosomes and a dark region called a nucleolus which makes ribosomes. (Ribosomes are necessary for protein synthesis.)
The nucleolus is contained within the cell nucleus. The nucleolus (/njuËËkliËÉlÉs/ or /ËnjuËkliËoÊlÉs/, plural nucleoli /njuËËkliËÉËlaÉª/ or /ËnjuËkliËoÊlaÉª/) is the largest structure in the nucleus of eukaryotic cells. It is best known as the site of ribosome biogenesis.