Answer:
The answer is B
Explanation:
pretty sure I'm too late by now sorry!!
Sand sheets and dunes cover approximately 25 percent of the Sahara's surface.
Answer:
B and C
Explanation:
B. In a given rock sample, the amount of Silicon-32 isotopes gets divided in half about every 170yrs.
This is the concept of half-life. Half life is the time take for half of a radioactive isotope to disintegrate. The shorter the half life the faster the isotope disintegrates.
From the question, we were told that it would take 170yrs for half of the isotope of Silicon to disintegrate to Phosphorus. This is the half life.
C. The half life can be used to determine the amount of Si-32 that has decayed from the time closure temperature was reached.
The closure temperature is very important in radioactivity. It is the temperature at which a system has cooled and there is no resulting disintegration of parent and daughter isotopes.
From first order kinetics, we know that the rate at which radioactive elements decay at any time is directly proportional to the number of radioactive atoms present. A knowledge of the half life helps to figure out the number of atoms that has decayed in time.
Answer:
Cylindrical map projections
Explanation:
Cylindrical map projections are used for portraying the Earth. Cylindrical map projections are rectangles, but are called cylindrical because they can be rolled up and their edges mapped in a tube, or cylinder. They have straight coordinate lines with horizontal parallels crossing meridians at right angles. All meridians are equally spaced and the scale is consistent along each parallel. The only factor that distinguishes different cylindrical map projections from one another is the scale used when spacing the parallel lines on the map.
Cylindrical map projections are great for comparing latitudes to each other and are useful for teaching and visualizing the world as a whole, by determining continents, languages, etc but really aren’t the most accurate way of visualizing how the world really looks in its entirety.
