____ are antibodies that activate the complement system
a. IgG and IgM
b. IgA and IgD
c. IgD and IgG
d. IgE and IgM
e. IgA and IgE
a
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Photosynthesis ceases when leaves wilt, mainly because _____
A) the chlorophyll in wilting leaves is degraded B) flaccid mesophyll cells are incapable of photosynthesis C) stomata close, preventing carbon dioxide from entering the leaf D) photolysis, the water-splitting step of photosynthesis, cannot occur when there is a water deficiency E) accumulation of carbon dioxide in the leaf inhibits enzymes
Arrange the following five events in an order that explains the mass flow of materials in the phloem
1. Water diffuses into the sieve tubes. 2. Leaf cells produce sugar by photosynthesis. 3. Solutes are actively transported into sieve tubes. 4. Sugar is transported from cell to cell in the leaf. 5. Sugar moves down the stem. A) 2, 1, 4, 3, 5 B) 1, 2, 3, 4, 5 C) 2, 4, 3, 1, 5 D) 4, 2, 1, 3, 5 E) 2, 4, 1, 3, 5
Where are nephrons found?
a. in mammals b. in insects c. in flatworms d. in annelids
Individuals of a certain tree species experience a markedly higher mortality rate at age 200 and beyond. Name two other changes you would expect in 200-year-old trees if this increase in mortality was accompanied by senescence
What will be an ideal response?