Answer:
Endoderm
Explanation:
The embryo has three germ layers. The ectoderm, mesoderm, and endoderm. The endoderm is the innermost layer. Other than the endocrine glands, the other tissues that develop from the endoderm are the gastrointestinal tract, urinary and auditory system, and the respiratory tract.
Answer:
The amount of oxygen in the atmosphere would decrease.
Explanation:
If a massive toxic spill kills off half the population of photosynthetic plankton in the ocean. That would mean that only half of the original population of plankton will remain. Photosynthetic plankton consumes carbon dioxide from the atmosphere during photosynthesis to produce energy and releases oxygen.