Identify whether the following variables are numerical or categorical. If numerical, state whether the variable is discrete or continuous. If categorical, state whether the categories have a natural order (ordinal) or not (nominal).

a. Number of sexual partners in a year

b. Petal area of rose flowers

c. Heartbeats per minute of a Tour de France cyclist, averaged over the duration of the race

d. Birth weight

e. Stage of fruit ripeness (e.g., underripe, ripe, or overripe)

f. Angle of flower orientation relative to position of the sun

g. Tree species

h. Year of birth

i. Gender