In mammals, The placenta is essential to the embryo for:

A. Nutrition, reproduction, and growth
B. Nutrition, respiration, and excretion
C. Locomotion, respiration, and excretion
D. Nutrition, reproduction, and excretion

Consider the model of the oxygen cycle on earth. the majority of earth's oxygen reservoirs are found in the a) atmosphere. b) biosphere. c) hydrosphere. d) lithosphere.

Imagine you are introducing the lac operan and the trp operon to students who have never learned about it before. complete the table to compare the similarities and differences between the two operons

Which of the following is an example of competition a. the leaves of a tree prevent a small shrub from getting sunlight. three species of birds feed a different heights in the same tree. b. three species of birds feed at different heights in the same tree c. zebra and giraffe’s feed on different grassland plants d. cats living in two different homes eat the same brand of cat food.