The founder effect is a type of genetic drift that occurs when a small group of individuals becomes isolated from a larger population, establishing a new population with a different allele frequency. This can lead to reduced genetic variation and increased prevalence of certain traits. Examples: high frequency of polydactyly in Amish community.
Assertion (A): Mycorrhizae are symbiotic associations between fungi and plant roots.
Reason (R): The fungus provides water and minerals to the plant and receives sugars in return.
A.A false, R true.
B.Both A and R are true, and R is the correct explanation.
C.Both A and R are true, but R is not the correct explanation.
Explanation:
Mycorrhizae enhance nutrient and water uptake for plants, and the fungus benefits from photosynthetic carbohydrates. It’s a mutualistic symbiosis. R correctly explains A.
Explanation:
Pinocytosis ('cell drinking') is a form of endocytosis where the cell membrane invaginates to take in a small droplet of extracellular fluid and dissolved solutes. Phagocytosis is 'cell eating' of large particles, exocytosis is secretion, osmosis is water movement across a semipermeable membrane.
Explanation:
The placenta is the organ that attaches to the uterine wall and facilitates exchange of nutrients, oxygen, and wastes between mother and fetus. The umbilical cord connects the fetus to the placenta. The amnion forms a protective fluid-filled sac.
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