Final answer:
Bacteria reproduce asexually through binary fission, where one individual splits into two genetically identical cells. Hydra can reproduce both asexually through budding and sexually through the production of gametes that form a zygote. Sea urchins reproduce sexually, releasing sperm and eggs into the water for fertilization.
Step-by-step explanation:
The concept of reproduction can be classified into two types: sexual and asexual reproduction. The organisms you've listed each represent different modes of these reproductive strategies. Let's clarify which organisms reproduce sexually and which reproduce asexually:
- Bacteria: These simple, prokaryotic organisms reproduce asexually through a process known as binary fission. In this process, a bacterium replicates its DNA and divides into two genetically identical daughter cells.
- Hydra: This freshwater organism is capable of both asexual and sexual reproduction. Asexually, it reproduces through budding, where a new individual grows from the body of an existing one and then detaches. Sexually, it produces gametes (sperm and eggs), which combine to form a zygote.
- Sea Urchin: As a marine animal, the sea urchin reproduces sexually by releasing sperm and eggs into the water (external fertilization). The union of these gametes leads to the formation of a zygote, which will develop into a new organism.