Lithified ash (or ash mixed with pyroclastic fragments) forms a volcaniclastic rock called a Tuff.
- A form of rock called tuff is created when volcanic ash is blasted from a vent during an eruption.
- The ash is transformed into a rock after ejection and deposition. Tuff is defined as rock with an ash content of more than 75%, whereas tuffaceous refers to rock with an ash content of 25% to 75%.
- The thickness of tuff often decreases with distance from the volcano and is usually greatest close to the volcanic vent. The typical shape of a tuff deposit is that of a "lens," not a "layer."
- Tuff may also be thickest on the vent's side that faces away from the wind or on the side facing the direction of the blast.
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<span>7 electrons in each outer shell
Group 17
Most reactive
Fluorine, Chlorine, Bromine, Iodine, Astatine
Alkali Metals:
1 electron is each outer shell
Group 1
Also reactive, but not as much as the halogens
Lithium, Sodium, Potassium, Rubidium, Cesium, Francium </span>
Non potable waters are not for drinking. It is not safe to be drink that's why drinking it can carry significant health risk on our body. Non potable waters are only for irrigation and other non drinking water activity. POtable waters are the water that is clean and safe to drink
Answer:
Gastrulation takes place after cleavage and the formation of the blastula and the primitive streak. It is followed by organogenesis, when individual organs develop within the newly-formed germ layers. Each layer gives rise to specific tissues and organs in the developing embryo.Cells in each germ layer differentiate into tissues and embryonic organs. The ectoderm gives rise to the nervous system and the epidermis, among other tissues. The mesoderm gives rise to the muscle cells and connective tissue in the body. The endoderm gives rise to the gut and many internal organs.
