Amphibian species worldwide have been in decline. A significant proportion of the decline seems to be due to the spread of the chytrid fungus, Batrachochytrium dendrobatidis (Bd). Chytrid sporangia reside within the epidermal cells of infected animals, animals that consequently show areas of sloughed skin and are lethargic. The infection cycle takes four to five days, at the end of which zoospores are released from sporangia into the environment. In some amphibian species, mortality rates approach 100%. Apart from direct amphibian-to-amphibian contact, what is the most likely means by which the zoospores spread from one free-living amphibian to another?

Water

Explanation:

The most likely means is water by which the zoospores spread from one living  amphibian to another because amphibians lives in water and these zoospores can move in water and reach another amphibian causing infection to them. Amphibians are the organisms which lives both land and water. They requires water for reproduction so they lives at wet places. Zoospores have a unique structure which able them to swim in the water. So water is a great source of dispersal of zoospores from amphibian to amphibian.

the answer is

c. parental

halogen, any of the six nonmetallic elements that constitute group 17 (group viia) of the periodic table. the halogen elements are fluorine (f), chlorine (cl), bromine (br), iodine (i), astatine (at), and tennessine (ts).