What does head-butting in bighorn sheep illustrate? a. competition among members of the same species b. competition among members of different species c. predator-prey relationships in bighorn sheep d. predation of members of the same species

Pulmonary arteries carry highly oxygenated blood. true or false?

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

Molecules like glucose and amino acids are not lipid soluble, so cannot cross the cell membrane by simple diffusion. instead, they are shuttled across by carrier proteins in the membrane from high to low concentration. does this process require energy from the cell? this is an example of what type of molecular movement?