Answer:
Reproductive cell cycle theory
Answer;
-Pure chemical substance and element
Explanation;
-Pure substances are substances that are made of only one type of atom or molecule.A pure substance can be either an element or a compound, but the composition of a pure substance doesn’t vary.
-An element is a pure substance that cannot be broken down into different types of substances by chemical means. All elements are pure substances. An element is composed of a single kind of atom. An atom is the smallest particle of an element that still has all the properties of the element.
-Tungsten is an element and therefore a pure substance.
Answer:
B. retain its urine in it’s blood stream
Explanation:
Sharks are cartilaginous fishes that lives in the ocean. Oceans are always salty, hence organisms need to maintain a salt-water balance between their internal and external environment because of osmosis. Sharks are able to maintain this by ensuring that the amount of solutes in their internal environment is as much as that in their external environment.
Sharks retain a chemical contained in urine called UREA in their bloodstream to counter the osmotic effect of the salt concentration in the waters they live. This helps them maintain a concentration balance with their environment.
<span>Maggie's training regimen may put her at risk to develop secondary amenorrhea. While amenorrhea is the absence of menstruation, secondary amenorrhea is the absence of the menstrual cycle in females who have started menstruating (having had at least one cycle) and then stop menstruating for a period longer than three months. Secondary amenorrhea occurs in times of extreme stress or weight loss (such as anorexia). Female soldiers have experienced secondary amenorrhea when they have gone to war or have become prisoners of war. Hormone shots, extreme weight gain, birth control, and certain medications also cause the condition.</span>
