Why do some species reproduce sexually and others asexually?

Because some species don't have a gender, therefore they have both make and female parts and are able to reproduce asexually.

I think.. heh.

Glucose, also called grape sugar, blood sugar or corn sugar, is among the simplest and one of the primary naturally occurring sugars. produced naturally by plants as the primary photosynthesis product, it is heavily used by living beings as a main energy source and is necessary for cellular respiration. chemically, it is a monosaccharide carbohydrate and serves as a building block for complex sugars like starch.