Chemoreceptors in the circulatory system detect changes in circulating pCO2. If CO2 concentrations get too high, the rate of ventilation increases. Why does this make sense?
A. It makes sense because CO2 is formed from O2 and, therefore, CO2 is a sign that oxygen is being consumed.
B. It makes sense because tissues that are more actively working produce more CO2 and, therefore, need more O2.
C. Actually, it does not make sense. There is no relationship between CO2 and ventilation rate.
D. It makes sense because hemoglobin carries CO2 and, therefore, blocks oxygen binding to the heme site, creating an oxygen deficiency.

the circled areas are referred to   as sunspots.   the sunspots are cooler than the   surrounding area.

sunspots are temporary phenomena on the photosphere of the sun that appear visibly as dark spots compared to surrounding regions. they correspond to concentrations of magnetic field flux that inhibit convection and result in reduced surface temperature compared to the surrounding photosphere.

the earth is thought to have been formed about 4.6 billion years ago by collisions from a cloud of hydrogen, helium, rock, ice and other materials. these were pulled together by gravity to form objects in and around earth like- asteroids and small early planets called planetesimals.

so, the best possible answer to this question will be option d- to harden materials to form different parts of earth’s layers