<h3><u>
Answer:</u></h3>
<u>(a) Reason for the heart beating fast:</u>
- When we exercise/run the muscles work hard and need more oxygen.
- So, when Ravi's heart beats faster more blood can be pumped to the muscles thus giving the oxygen required.
<u>(b) Organs involved along with the heart to help Ravi complete his race:</u>
- The main organs involved along with the heart are quadriceps, hip flexors, hamstring, glutes and calf muscles.
- The nervous system, muscular system, skeletal system, respiratory system and circulatory system function effectively when a person runs.
<span>Phytoplankton are primary producers and are the foundation of the aquatic food web. They feed everything from microscopic, animal-like zooplankton to multi-ton whales. Small fish and invertebrates also graze on the plant-like organisms, and then those smaller animals are eaten by bigger ones.</span>
B Mutation i think hope this helped
<em>Direct </em><em>Contact</em><em> </em><em>Infection</em>
<em>Direct</em><em> contact are touching, kissing, contact with oral secretions, or contact with body lesions.</em>
<em>Hope</em><em> </em><em>it</em><em> </em><em>helps</em><em> </em><em>(⌒▽⌒)</em><em>(⌒▽⌒)</em>
C. Sperm is produced in a male organism by meiosis