Early in development, the nervous system begins as a . A. tube surrounding a fluid-filled cavity B. spherical structure in the center of the embryo C. diffuse system of cells scattered throughout the body D. single layer of cells covering the heart and other internal organs

The images show fossils of a modern bird and two extinct organisms (a tyrannosaurus rex and an archaeopteryx). based on the structure of the three organisms, it can be concluded that . the archaeopteryx and bird have wings, while dinosaurs have limbs. so, it can be concluded that .

What organ systems are working to you cool down after a workout?

Prior to the mt. st. helens eruption on may 18, 1980, satellite and topographic views of the volcano were captured. based on the topographic map of mt. st. helens, what is the contour interval if the volcano height is 2,950 m? question 9 options: 600 m 400 m 750 m 500 m