These are known as Hormones. Hormones are chemical messengers that are released in one tissue normally endocrine glands for example, adrenal glands, pituitary glands, and transported in the blood stream to alter the activities of specific cells in other tissues. Hormones serves as messengers, controlling and coordinating activities or processes such as growth, metabolism and fertility in the body.
Answer:
Yes, your answer, nitrogen, is correct (the most appropriate option). However, oxygen is also a correct option.
Explanation:
Nitrogen exists on its own as a diatomic gas. However, it exists as organic nitrogen in nucleic acids such as DNA and RNA (as part of their nitrogenous bases) and in the amino (--
) group of amino acids.
Do note that a case can also be made for oxygen as a right option: like nitrogen, it exists as a diatomic gas and can be found in both nucleic acids and in the carboxylic group of amino acids.
Sulfur is not an appropriate option as nitrogenous bases (and nucleic acids) to the best of my knowledge do not contain sulphur although some amino acids like cysteine do.
Carbon is not also an appropriate option because elemental carbon does not exist in gaseous form even though it can be found in both nucleic acids and amino acids.
B, because of the dry climates, they need to retain as much water as they possibly can.
Answer:
the petrified log looks like the original tree.
Explanation:
A tree to be petrified first needs to be buried. An element laying on the surface can not be petrified because it is exposed to many different factors (such as<em> organisms, microorganisms, climatic conditions</em>, etc.), that affect the petrification process. So, in the case of a fallen tree, first, it needs to be covered by many sedimentary layers. Once it is underground, it also needs the presence of underground water and minerals. Water replaces the original organic material with minerals (silica, calcite, and pyrite). This replacement process results in the conversion of the woody material into a fossil of the original material. Very often, the tree details are so preserved that the fossil looks exactly like the original trunk.
Depending on the preservation degree, a fossil can be useful for different studies about the past.
