A normal heart rate ranges between 60-100 beats per minute. The higher the heart rate is, the faster the blood is pumping through the heart. When exercising a persons heart will be higher because the brain and the muscles in the body are in need of oxygen so the heart needs to pump faster in order to sustain optimal performance.<span />
        
             
        
        
        
Answer:
<u>Sister chromatids are identical  forms of chromatids  of a chromosomes. They are mostly  formed by semi-conservative replication of DNA molecule of a single  chromosome.Thus they  are  like  </u><u>'photocopies' </u><u> of  original parent  chromosomes; joined together at the Centromere</u>.
They are exactly similar in all ramification; with the same gene and allele compositions..
<u>However; slight differences  arise between the two identical sisters due to  </u><u>mutation</u><u> from</u><u> errors </u><u>at replication;and also in  the  length of telomere repeats.</u> 
Non-sister chromatids are dissimilar forms of  chromatids of a chromosomes formed  when each half of  a chromosome  at fertilisation from separate   haploid sex-cells, of each parent. fused.They contain different genetic composition;because  they are not on the same homologous chromosomes.Therefore crossing -over ensure variation.
<u>However, they are genetically  similar in composition; if they  are contained in homologous chromosomes</u>. This is because Synapsis of bivalent of these chromosomes allow genetic material to be shared by  chromosomal crossing-over between the non-sister chromatids  on the chromosomes ; therefore identical genetic characteristics are shared .
Explanation:
 
        
             
        
        
        
Clostridium botulinum is an anaerobic, spore-forming, bacterium organism that releases a toxin that causes muscle relaxation. The toxin that is released is a neurotoxic protein: Botulinum toxin (BTX) and <span>is produced only in an anaerobic environment. </span>This toxin is used as a a medicine to treat overactive muscle movement. 
        
             
        
        
        
The answer is D, algae.
—Evidence—
•] Protozoan definition: a single-celled microscopic animal of a group of phyla of the kingdom Protista, such as an amoeba, flagellate, ciliate, or sporozoan.
•] it does not feature algae, therefore it’s D.