I think it's the first and second option but I could be wrong because I don't know much about deserts :)
Chromosomes are made of condensed coils of DNA. Genes are segments on a chromosome that carry the code for a specific trait. Alleles are contrasting forms of a gene. Dominant means that a particular trait will be visible. Recessive means that a trait will be hidden (unless it is paired with another recessive gene). A trait is how the gene is seen. For example, eye color is a trait.
Ok ok no fret im here to help as best as i can :)
Weathering is a process that breaks down or changes rocks into smaller
pieces. Various atmospheric aspects are responsible for weathering
processes. Weathering is different from erosion. Erosion is the movement
of rock pieces and sediment from one area to another. Weathering is the
breaking down of rocks and erosion is a wearing away of rocks. There
are two main types of weathering: physical (or mechanical) weathering
and chemical weathering. Quite often, both forms of weathering will
occur together
Physical weathering is also known as mechanical weathering. This type of
weathering occurs when rocks and other landforms are broken down by
physical factors in the environment. These physical factors include
wind, water, sun, ice and temperature changes
Molten material is allowed to solidify into the final shape.
Casting defects occur during solidification:
Gas porosity
Shrinkage
Two stages of solidification:
Nucleation
Growth