Normally when you sit up or stand, gravity pulls some of your blood down to your belly area, hands and feet. In response, your blood vessels quickly narrow and your heart rate increases slightly to maintain blood flow to the heart and brain, and prevent blood pressure dropping.
Normally when you sit up or stand, gravity pulls some of your blood down to your belly area, hands and feet. In response, your blood vessels quickly narrow and your heart rate increases slightly to maintain blood flow to the heart and brain, and prevent blood pressure dropping.
1. rise of angiosperms 2. rise of chemoautotrophs and photoautrophs 3. rise of multicellularity 4. rise of bryophytes 5. rise of gymnosperms 6. rise of eukaryotes 7. rise of cyanobacteria
