Chromosomal deletion is the loss of genetic code, caused by a segment of chromosome breaking away during DNA replication. The best answer is the third one, "when part of a chromosome breaks off and does not reattach."
Pick the one that gets to your heart
A mutation is a change in a DNA sequence. Mutations can result from DNA copying mistakes made during cell division, exposure to ionizing radiation, exposure to chemicals called mutagens, or infection by viruses. Germ line mutations occur in the eggs and sperm and can be passed on to offspring, while somatic mutations occur in body cells and are not passed on.
Recessive mutations inactivate the affected gene and lead to a loss of function. For instance, recessive mutations may remove part of or all the gene from the chromosome, disrupt expression of the gene, or alter the structure of the encoded protein, thereby altering its function.
The first answer is the correct one. Osmosis is only water and diffusion is everything else across a semi-permeable membrane.
