The answer is A.True but they are not the only ways in which this can occur.
Law of Superposition
a basic law of geochronology, stating that in any undisturbed sequence of rocks deposited in layers, the youngest layer is on top and the oldest on bottom, each layer being younger than the one beneath it and older than the one above it.
There are small tubes that connect all parts of a plant or a tree with the root. The root then applies root pressure to the nutrients and the nutrients and the water are pumped towards the upper parts through these small tubes.
Answer: D. It yields chromosomes that contain both maternal and paternal DNA.
Explanation:
The recombination or crossing over is a genetic process. It takes place during the Prophase I of meiosis. The homologous pair align and held together by synapsis. This results in the mixture of genes combination formed from both parents that can be represented as a single chromosome.
If the recombination do not occur then each chromosome will be either 100% maternal or paternal. Thus recombination assures the recombinant chromosomes which consists of genetic material from both parents. Thus the genetic diversity of offspring increases.