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.
For most adults, normal heart rate is 60 to 80 BPM. Well-trained athletes can have a normal heart rate of 40 to 60 BPM. When you work out, your heart rate will get higher. This is called your active heart rate. Active heart rates, like resting heart rates, differ in people and change as you age. Generally, a healthy active heart rate is 60 to 80 percent of your maximum heart rate, or the highest your heart rate should safely go.