Physical change. Boiling water does not change the fundamental properties of the water, as it can turn back into water during condensation.
<span>The answer is D) atmosphere. There are four spheres of the Earth: 1. Lithosphere (from Greek word 'lithos' = rock), 2. Hydrosphere (from Greek word 'hydros' = water), 3. Biosphere (from Greek word 'bios' = life), and 4. Atmosphere (from Greek word 'atmos' = air). Condensation is the change of water vapour into the water, i.e. the change of water from its gaseous form into liquid form. Since water vapour is the part of air, condensation occur in the atmosphere.</span>
A) Crossing over is the mechanism of genetic variation that results from the exchange of gene segments between non-sister chomatids.
<span>Cells control cell division in order to maintain normal cell function. If something happens to the control of the cell division, the healthy cells will divide uncontrollably. These new cells are cancer cells. </span>
The mutations in three genes are responsible for development of cancers:
1. Mutation in proto-oncogenes. Proto-oncogenes normally signal cells to grow and differentiate. Proto-oncogenes can become oncogenes due to mutations which result in the uncontrollable division of the cells.
2. Mutation in tumor suppressor genes. In normal cells, tumor suppressor genes suppress genes essential for cell cycle and that way they prevent uncontrollable cell division. However, after a mutation in these genes, suppression is lost and the cell may progress to cancer.
3. Mutation in stability genes. In normal cells, they have no role either in cell death or growth, but they control mutation rate. Mutation in stability genes results in situation where all genes, including proto-oncogenes and tumor suppression genes, are more frequently mutated.
Answer:
Cell walls
Explanation:
virtually all bacteria contain peptidoglycan in their cell walls; however, archaea and eukaryotes lack peptidoglycan. Various types of cell walls exist in the archaea. Therefore, the absence or presence of peptidoglycan is a distinguishing feature between the archaea and bacteria
