1. what causes the autorhythmicity or action potentials of the nodal cells? a. a decrease in chloride permeability b. a gradual calcium efflux or movement out of the cell c. a gradual depolarization of the cell membrane until threshold is reached d. a gradual repolarization of the cell membrane until threshold is reached

The correct answer will be option-C

Explanation:

The rhythm of the heartbeat is controlled by the pacemaker of the heart called the sino-atrial node.

The SA node generates action potentials which trigger the contraction and relaxation of the atrium and ventricles. The membrane potential generation initiates by the depolarization of the cell membrane when the L type of Ca⁺² ions opens up and calcium ions enter the cell.

This depolarizes the cell until the potential threshold is reached which lies between the -40 and -30 mV.

Thus, Option-C is the correct answer.

x would be the most and the least would be y because there are more fruit   and seeds than flock z has insects

picture a world where computers are building made-to-order personalized robotic arms and synthetic organs, drones are circulating above mars! due to the rapid growth of technology, the future has never been more unpredictable, and it presents a huge challenge in education: we are teaching students how to work in a future that we have never been unsure of. it is widely predicted that in eight years’ time, there will be more jobs in the fields of science, mathematics, technology and engineering than in any other discipline. and, as the technology continues to develop, it will soon become clear that addressing social problems will involve more innovative thinking, and analytical and technical knowledge than ever before. undeniably, there are no subjects that encourage innovative and creative thinking, deep thought, problem solving and independence more than the stem subjects. while it is widely commented on that there is a need to reimagine the ways stem subjects are taught in schools by embracing a more interactive and innovative approach to appeal to more students, it should come as no surprise that some of the most reputable educational organizations in the world are already implementing changes to embrace stem. harvard, for example, announced in 2014 that they were increasing their computer science faculty by over 50% and has since introduced computer science as a core subject for all freshmen. the urgency of supporting stem subjects at a young age is becoming more relevant than ever, as adopting a keen interest in the curricula needs to happen early. however, beyond the age issue is one of gender.

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