From the deepest to most superficial: pia mater, arahnoid, dura mater
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.
Answer:
The nitrogenous bases in DNA are adenine (A), guanine (G), thymine (T), and cytosine (C).
Explanation:
Replication is the process where DNA molecules copies itself to form another DNA molecule during cell division. it involves several enzymes which includes DNA helicase, the enzyme that unwounds the DNA double helix. RNA primase, it is an enzyme that creates an RNA primer. DNA polymerase, it is the enzyme that matches and lays down nucleotides to form the new DNA daughter. DNA ligase joins the Okazaki fragments by catalysing the formation of phosphodiester bond.
