Answer:
They affect cancerous cells during a particular phase of cellular reproduction.
Explanation:
Cell cycle-specific drugs are chemotherapy drugs including cancer, they kill cancer when the cancer cells when they're dividing or active, unlike cell cycle non specific that kills cancer when cells when at rest mode.
Usually considered to be the most effective against tumor in cancer patients.
For example, the following are some of the antitumor antibiotics are:
Anthracyclines: Mitoxantrone and Idarubicin.
Chromomycins: Dactinomycin and Plicamycin.
Miscellaneous: Mitomycin and Bleomycin
The correct answer is - oxygen.
The phytoplankton and the microscopic marine plants are using the process of photosynthesis in order to produce energy for them. In order for this process to take place, two things are needed, sunlight and carbon dioxide. The consumed carbon dioxide is not totally used, but there's some waste from it. The waste is actually the oxygen. The oxygen is released and it gets back into the atmosphere. This gas is crucial for the survival of the living organisms on the planet, especially the animals, so it is extremely import that the environment of the phytoplankton and the microscopic marine plants is not destroyed, as they are the ones that release the biggest amount of oxygen into the atmosphere.
I would say the Geosphere, as Biosphere, Hydrosphere, and Atmosphere don't quite fit Volcanology.
