1) B
(I'm not so sure of this one) All of the other options have a steady impact on population regardless of the density of organisms except competition
2) D
Increased carbon dioxide levels would not hinder plant growth, and tsunamis aren't really linked to carbon dioxide levels. Increased carbon dioxide is unlikely to lower the air temperature so only D is left.
3) A
4) Three properties of water that allow it to sustain life are that it is adhesive, it is a good solvent, and cohesion. Adhesion is important in situations such as water travelling up xylem tubes in plants so that the water is not pulled down by gravity and can reach parts of the plant that need water. Cohesion allows the water being pulled up the xylem to stay together and for water molecules to be pulled when a neighbouring one is moved. Water being a good solvent allows inorganic minerals to be taken with water through vascular tissue, such as in the previous example.
Nuclear DNA is present in the nucleus of eukaryotic cells. When working with the DNA samples, the best source of nuclear DNA is hair root that anchors the whole shaft of hair. Hair root possesses cells that are called as keratinocytes.
The answer in the spaces provided is venture and calamity. The answer is venture because sky-diving is considered to be a an activity that seems to be adventurous and dangerous in which venture means while it also results into calamity because it causes distress in which she has injured herself.
Food takes about 6 to 8 hours to completely pass through the digestive tract.
