1. A rock sample has a mass of 16 grams: and a volume of 8 cubic centimeters.
When the rock is cut in half, what is
the volume and density of each piece?
(1) 8 cm3 and 0.5 g/cm3
(2) 8 cm² and 1.0 g/cm3
(3) 4 cm' and 2.0 g/cm3
(4) 4 cm3 and 4.0 g/cm3
1

(3) 4 cm' and 2.0 g/cm3

Explanation:

Given:

volume= V= 8 cm³

mass= m= 16 g

The density is the mass per volume of a substance, so the density of the rock is:

density= d= 16 g/8 cm³= 2 g/cm³

When we cut the rock in half, we have a half volume and a half mass:

V= 8 cm³/2= 4 cm³

m= 16 g/2= 8 g

But the density is not altered because it is an intrisic property - it does not change with the amount of subtance. Thus, the density of a half rock is:

d = m/V= 8 g/4 cm³= 2 g/cm³

parasites can detrimentally affect their host, but also must not allow their host to die before they can complete their life cycle. some parasites have complex life cycles with many different hosts, and have had to find ways of persisting in many different environments during the change from one host to another. ectoparasites live outside the body of the host, and can more easily  disperse, but are  more exposed to predators, parasites, parasitoids. endoparasites live inside the body of the host, and are therefore protected from the outside environment. but they can be  attacked by the host's immune system. they have therefore developed  mechanisms for dispersal such as  complex life cycles.