What two celestial objects do we often use as our standard candles

Flock x flock y flock z total pieces of food eaten (from previous page) 147 93 60 food percentage* % % % simulated number of birds in flock for 3rd generation** * divide each flock's total pieces of food by 300, the total number of pieces of food eaten. ** multiply the food percentage for each flock by the total number of birds (30).

Why is excretion necessary to maintain homeostasis?

Chloroplasts and bacteria are in size. a. similar b. at different ends of the size range c. exactly the same d. none of these