Los jugos gástricos presentes en el estómago tienen un pH de aproximadamente1.87 ¿Cuál es la concentración de iones H+ presentes en los jugos gástricos?

Astudent reads the following text in a science book: scientific evidence tells us that the cause of earths four seasons is the tilt of earth as it revolves around the sound the student is instructed to illustrate this information in a science book. how will the student illustrate winter in the northern hemisphere? a. earths northern hemisphere will tilt away from the sun. b. earths northern hemisphere will tilt toward the sun. c. earths orbit will be farther away than from the sun d. earths southern hemisphere will tilt away from the sun.

Veins have a much lower blood pressure than arteries. which of these prevents backflow of blood in veins? a. pressure applied by the heart b. one–way valves in veins c. thin muscular walls of veins

Explain why it’s important for scientists to study the sun. list at least two challenges researchers face when examining earth’s nearest star.