A. Water being pumped in and out of guard cells.
Answer:
He was the first to observe live cells in a sample of pond water with the use of a microscope.
Explanation:
Anton van Leeuwenhoek is universally known as the Father of Microbiology.
He was the first person to discover a living cell under a microscope. He discovered protozoa (the single-celled organism) and named them animalcules.
Answer:
A. the heterozygote advantage
Explanation:
Heterozygote advantage is the condition where the heterozygous individual has higher relative fitness than both homozygous dominant and homozygous recessive individual. This means that the heterozygote individual has higher chances of surviving than both the homozygous counterparts. Sickle cell anemia is a recessive inherited disorder in which oxygen carrying hemoglobin has an abnormal structure. Hence, the resultant RBCs are not spherical but have crescent sickle shape. The oxygen carrying capacity of such RBCs is drastically reduced but they are unaffected by malarial parasite due to their abnormal structure.
- A person with both the recessive genes for sickle cell would not be able to survive due to insufficient oxygen transport in body.
- A person with both the dominant genes would be free of sickle cell anemia but in case of malaria would not be able to survive as the normal RBCs would be hijacked by the parasite.
- A hetrerozygote would survive both in malaria and sickle cell condition since he has enough normal RBCs for oxygen transport but also has sickle cell RBCs which are unaffected by malarial parasite.
