What is true of matter in ecosystems?
a. the primary productivity of an ecosystem does not depend on the availability of nutrients.
b. living things can recycle elements within an ecosystem as long as decomposers are present.
c. matter flows in a one-way direction with a 10% loss at each move up in trophic level.
d. elements continuously cycle between the physical environment and living organisms.

1) gene flow

- it is described as the transfer of genes from one population to another population so that frequency of gene is increased.

-a zebra migrates to join a different herd of zebras.

2) natural selection

- a mechanism of evolutionary change in which individuals with advantageous traits survive and reproduce whereas the others ( those that can not adapt) eliminate from the population.

-competition for sunlight leads to taller trees.

3) mutation

- permanent change in the nucleotide sequence of dna ( genetic material) that could have harmful or useful consequences.

-the dna of a snake changes to make its venom stronger.

4) genetic drift - it is a random phenomenon ( that occurs by chance such as fire) that results in change in the gene frequency in a small population.    

-a grassfire randomly sweeps through a population of buffalo and kills most of the animals.

explanation:

yes its like the dead sea which is full of salt which makes you stay afloat

so yes an egg will float in salt