Answer:
A DNA marker
Explanation:
also known as a size standard or a DNA ladder) is loaded into the first well of the gel. The fragments in the marker are of a known length so can be used to help approximate the size of the fragments in the samples.
 
        
             
        
        
        
Water drains into the sinkhole pollution due to factories 
The lake was created as limestone gradually dissolved, causing the sediment layer above it to collapse and creating the lake basin. Low lake levels and slow draining can be caused by bottom leaks, sinkholes, and swallets, long-term dryness, and a lack of recent, strong rainfall events.
<h3>What causes lake Jackson to disappear ?</h3>
Before the lake dried up, those walking along the shore of the sinkhole at Lake Jackson on Thursday would have been in three to four feet of water.
- Environmentalists refer to the process as a "dry down," and it occurs every ten or twenty years. The likelihood of causes includes dry weather, a lack of rain, and a decreased water table.
- The lake will typically begin to fill again after the sinkhole plugs itself, sometimes taking years to do so pre sinkhole level
Learn more about Lake Jackson here:
brainly.com/question/23942365
#SPJ4
 
        
             
        
        
        
Answer:
A
Explanation:
when light is limited photosynthesis will be slowed so the euglena will prefer to ingest food...light is needed for photosynthesis 
 
        
             
        
        
        
Answer:
Eggs are developed and released by the <em>ovaries.</em>
Sperm is produced by the <em>testes</em>.
Explanation:
Ovaries are the site in females where the production of egg takes place. After the formation of an egg, the egg is transported to the fallopian tube, where it might undergo fertilization if a sperm unites with it. 
Sperms are the male reproductive cells which are produced by many animals. The sperms are produced in the testes of males. 
The sperm and the egg unite to form a fertilized zygote.