Answer:
D. They define geological periods because scientists use them as reference points for tracking the history of the earth.
Explanation:
Catastrophic events related to changes in geological timeline are very useful in defining geological periods.
These events have very significant appearance in the geological record and can be used to determine the history of the earth.
The catastrophic events usually culminates into extinction cycles or termination of some organisms from the earth surface.
Geologists use these events that are often wide spread to delineate geological periods.
Enzymes.
because enzymes are a substance produced by a living organism that acts as a catalyst to bring about specific biochemical reaction.
Answer:
Insulin is a protein hormone which binds to the membrane receptor where as steroid hormones bind to the intracellular receptors.
Explanation:
Hormones can be divided into two groups based on their binding with receptor. Some hormones are water soluble like protein or peptide hormone (example is insulin) and catecholamines. These water soluble hormones cannot cross the plasma membrane of the target cell and thus bind to the membrane receptor. Binding to the membrane receptor leads to activation of intracellular enzymes which bring the physiological change. Steroid hormones in the other case can cross the plasma membrane and then bind to the intracellular receptors. The hormone receptor complex then either binds or activates specific portion of DNA to bring the physiological change.
Insulin is made by beta cells islets of Langerhans in the pancreas. It controls the levels of glucose. It is a small protein made of two polypeptides, one of 21 amino acids and the other of 30 amino acids. These two are called A chain and B chain and are linked together by disulphide bonds. The pro-hormone contains an extra stretch called C-peptide. During the maturation process the proinsulin looses the c-peptide to become mature insulin protein hormone. An american company called Eli Lilly, for the first time made recombinant human insulin.
The two body systems that will be directly affected if a tendon gets torn and cannot function properly is the muscular system and the skeletal system. The correct answers are B&C.
Answer and Explanation:
Engine irrigation pumps are used to propel water into the irrigation channels, providing full water supply to agricultural crops. The use of the engine pump has advantages and disadvantages. Among the advantages, we can present the simplicity of operation of these pumps, being easily operated efficiently. They also save energy and are essential for irrigation with more viscous liquids, when necessary. This feature is the main reason for using this type of pump.
Among the disadvantages we can say that these pumps have a slower and less accurate work.
