Blood pressure is measured with which device?

his week a heat wave will be hitting, and most of the country will be experiencing temperatures above average for july. due to humidity, the temperature outside can feel even warmer than it actually is. this adjusted temperature, often referred to as the “feels like” temperature is called the heat index. the chart shows the heat index, which is calculated based on temperature and relative humidity. use this chart to answer the following questions.  

answer; i believe its the red blood cells; plz check first good luck