About 99% of the solid Earth is made up of A.
about half of the known elements.
B.
a small fraction of the known elements.
C.
just one of the known elements.
D.
most of the known elements.

Some plants rely on the wind to reproduce an example is it’s important for plants to use the forces of nature to reproduce because 1. 1a white tuft of dandelion seeds 2a spiked burrs surrounding seeds 3a hard shell on a walnut? 2. 1b require pollination to reproduce 2b reproduce only asexually 3b cannot move about freely?

Aperson with age is more likely to catch diseases that healthy people usually don’t catch.what are these infections called?

The vaccine in a flu shot contains weakened flu viruses. how does a flu shot work with the immune system? a. it destroys lymphocytes. b. it destroys macrophages. c. it activates macrophages. d. it activates lymphocytes.