Explain the statement "the lower down in the food chain we eat, the greater percentage of solar energy we put to use, and the more people earth can support" in terms of trophic levels and pyramids of energy.

The particle p starts from rest at point a at time t = 0 and changes its speed thereafter at a constant rate of 2.8g as it follows the horizontal path shown. determine the magnitude and direction of its total acceleration (a) just before point b, (b) just after point b, and (c) as it passes point c. state your directions relative to the x-axis shown (ccw positive) and choose the angle with the smallest magnitude.