Answer: a. Measuring the amount of rain that falls in a 24-hour period in a rain gauge.
Access Control Points
They are restrictions points that enforce regulations and guidelines on decontamination when exiting the sites and ensuring adherence safety standards when entering the site. The regulation are usually, as standard practice, conspicuously posted at the Access Control Points.
Access Control Points are usually set up at the periphery of the Exclusion Zones, and ideally, there should be a separate entrance and exit Control Access Point.

<h2>Fixation</h2>
Nitrogen in its gaseous form (N2) can’t be used by most living things. It has to be converted or ‘fixed’ to a more usable form through a process called fixation. There are three ways nitrogen can be fixed to be useful for living things:
<h3>Biologically: </h3>
Nitrogen gas (N2) diffuses into the soil from the atmosphere, and species of bacteria convert this nitrogen to ammonium ions (NH4+), which can be used by plants. Legumes (such as clover and lupins) are often grown by farmers because they have nodules on their roots that contain nitrogen-fixing bacteria.
<h3>Through lightning: </h3>
Lightning converts atmospheric nitrogen into ammonia and nitrate (NO3) that enter soil with rainfall.

Answer:
11) A. The optimum pH of an enzyme is 6.6
12) C. A control group
Answer:
The correct answer is option d. "Many species that moved into North America from South America outcompeted the endemic taxa and still exist today".
Explanation:
The Great American Biotic Interchange (GABI) was an historical period at which numerous species from South America migrated to North America, and numerous species from North America migrated to South America because of the formation of the Isthmus of Panama. During this event, many species that moved into North America from South America outcompeted the endemic taxa and still exist today. The species that successfully immigrated to South America and exist today were mostly small mammals, such as armadillos and opossums.