cones are specialized reproductive structures of the sporophyte. Each cone consists of several âscalesâ arranged around an axis. Each scale is a sporophyll that will bear the spores of the sporophyte generation. An ovulate cone has many hard, radiating scales, each bearing a pair of ovules. Pollen cones are generally much smaller than ovulate cones; they contain many sporangia, each of which makes numerous haploid spores by meiosis. Male gametophytes (pollen grains) develop from the spores.
Bradycardia was defined as a heart rate less than 60 beats per minute when textbooks asserted that the normal range for heart rates was 60â100 BPM. The normal range has since been revised in textbooks to 50â90 BPM for a human at total rest.
1 The resting adult heart rate is normally 60 to 100 beats per minute. 2  Athletes or people on certain medications may have a lower resting normal rate. 3  The normal heart rate for children aged 1 to 8 years is 80 to 100 beats per minute.  The normal heart rate for infants age 1 to 12 months is 100 to 120 beats per minute.