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.
The correct answer is B. The parents are heterozygous with polka-dot tails, so they both have Pp genotype. The combination of their genotypes (Pp x Pp) could produce 4 genotypes PP, Pp, Pp and pp. Therefore, there is 25% chance for a PP genotype, 25% for a pp genotype and 50% for a Pp genotype. The PP and Pp genotypes produce a polka-dot tail phenotype and the pp genotype produces a solid coloured tail phenotype. In conclusion, there is 75% chance for a polka-dot tail (25% for a PP + 50% for a Pp) and a 25% for a solid coloured tail phenotype (25% for a pp).
Evidence for evolution is provided by homologous structures. These are structures shared by related organisms that were inherited from a common ancestor. Other evidence for evolution is provided by analogous structures.
This could be the different times you did the experiment
