Explain how the level of oxygen and carbon dioxide in the blood will trigger the respiratory center

Which events are likely to be catastrophic to an ecosystem? select the three correct answers.a-hurricane.b-steady population growth.c-seasonal flooding.d-introducing of an aggressive invasive species.e-tsunami.

The following image is of a diatom. it lives in water and gets food from photosynthesis. it is encased in a hard shell made of something similar to glass or sand . a diatom is a(n) because it has a) multi-celled organism; specialized parts. b) vertebrate; a skeleton. c) insect; an exoskeleton. d) single-called organism; only one cell.

What occupation did muhammad have before the first revelation