С ixl. com/science/grade-7/describe-popula tions-communities-and-ecosystems
DD
A terrarium is a garden that is grown
in a glass container. When the
container is open to allow evaporation,
it becomes a good habitat for plants
from dry environments. To allow the
soil to drain so it does not get too wet,
people add crushed rocks to the soil.
Succulents are plants that store
water in their leaves and stems,
allowing them to survive in dry
environments. Succulents such as
pincushion moss, echeveria, and moon
cactus grow well in an open terrarium.
planting succulents in a terrarium
In a terrarium, the pincushion moss, the echeveria, and the moon cactus make up which of
the following? Select all that apply.
a population
part of a community
part of an ecosystem

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:

answer: substrate concentration. enzymes work best when there is a high enough substrate concentration for the reaction they catalyse.

the titanic would be the correct answer