Why do i need a flu shot every year, while many other vaccinations last years or even a lifetime?

Which of the following statements about protists are true? a. they are typically found in moist environments. b. they are all unicellular. c. they have a nucleus. d. they are all multicellular.

What's wrong with this ecological pyramid? (multiple choice)1. secondary consumers should be at the bottom of the pyramid2. the sun has an arrow leading to decomposers 3. primary consumers should come after the sun4. energy retained should increase from the bottom to the top5. the sun should be at the bottom of the pyramid

Internal feedback works to maintain homeostasis when your a. heart rate decreases as your white blood cells increase b. breathing rate decreases as your red blood cells decrease c. heart rate increases as your liver is cleaning blood d. breathing rate increases as your heart rate increases