A graph of atmospheric carbon dioxide concentration over time is shown below.
CO, Concentration (ppm)
Change in Atmospheric CO2
Concentration over Time
380
360
340 -
320
300-
280 -
200-
240-
220 -
200+
Scientists are investigating the cause of the large increase in
atmospheric carbon dioxide concentration since about 1800.
Which of the following provides the best explanation for the
increase?
A. eruptions of large volcanoes
B. use of fossil fuels by humans
C. natural fluctuations of climate
D. photosynthesis by photoplankton
1000 1200 1400 1600 1500 2000
Year

it's the cell cycle, but cytokines is when the cell divides.

theres 3 stages interphase,mitosis,and cytokines.

interphase prepares the cell for division.

mitosis is the process of dividing the cell,it has 4 parts interphase,anaphase,metaphase,and telophase.

lastly there's cytokines,that's when the cell divides into 2 daughter cells

what statement best describes the difference between the sympathetic and parasympathetic nervous systems?

the sympathetic nervous system prepares the body for intense physical activity and is often referred to as the fight-or-flight response. the parasympathetic nervous system has almost the exact opposite effect and relaxes the body and inhibits or slows many high energy functions.

blood enters the heart through two large veins, the inferior and superior vena cava, emptying oxygen-poor blood from the body into the right atrium of the heart. as the ventricle contracts, blood leaves the heart through the pulmonic valve, into the pulmonary artery and to the lungs where it is oxygenated.