12. In what direction does blood flow through the heart? A. Up and down
B. Right to left
C. Slow then fast
D. Fast then slow

Ascience research group is testing a new type of plant food. one trial is conducted in a controlled experiment. the data from the trial show that the plant that received the new food grew faster than the control plant. the group announces that the new plant food makes plants grow faster. what is the main weakness in this scientific claim?

1. isogamy 1 organisms with gametes of the same size and shape 2. anisogamy organisms with gametes of different sizes and shapes 3. oogamy 2 organisms with gametes of the same shape but different sizes 4. gonads gamete-producing organs in lower plants 5. gametangia gamete-producing organs in animals

The cellular plasma membrane is selectively permeable, which means some materials move through it while others cannot. the movement of materials into and out of the cell is called membrane transport. this activity will you identify the different mechanisms of membrane transport