Peptones and beef extract
MacConkey agar is a selective and differential culture medium for bacteria designed for isolation of Gram negative and usually enteric bacilli, based on their ability to ferment lactose. It contains bile salts, crystal violet, neutral red dye. There are many variations of MacConkey agar depending on the need. This medium was developed by Alfred Theodore MacConkey. This agar can distinguish gram negative bacterias that can ferment. This is known as the indicator medium.
The top layer would be most likely to have closer similarities to the organisms found today. hope this helps.
Answer:
B. the most limited resources required for survival
Explanation:
The population and survival of organisms in any ecosystem is usually dependent on the availability of a number of resources, which may include water, food, space, sunlight, and other environmental conditions.
However, what determines the maximum number of organisms that an ecosystem can adequately cater for or sustain is the most limited resources required for the survival of that organism in that ecosystem. The carrying capacity of an ecosystem is dependent on the most limited resources required for sustenance of that organism
