Define the terms unisexual and bisexual giving one example of each.

Unisexual: In most of the animals including humans, male and female reproductive organs are in different individuals. Such animals are called unisexual.
Bisexual: In some animals like tapeworm, liver fluke, earthworm, leech, etc., the male and female reproductive organs are found in a single individual. Such organisms are called bisexual (hermaphrodite). The flower may be unisexual (e.g., papaya, watermelon) when it contains either stamens or carpels. and bisexual (e.g., Hibiscus, mustard) when it contains both stamens and carpels.

Unisexual is the plant whose flowers contain either stamens or carpels but not both. 

Example: Papaya, Watermelon. Bisexual is the plant whose flowers contain both stamens and carpels. Example: Hibiscus, Mustard.