Secondary cell walls are stronger than primary cell walls because secondary cell walls contain
a. more pectin.
b. less lignin.
c. more chitin
d. more lignin
e. layers of cellulose fibrils at various orientations to one another.
Ans: d. more lignin
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Answer the following statements true (T) or false (F)
1. Catabolic and anabolic reactions in living cells involve the transfer of electrons from one molecule to another in reduction-oxidation reactions. 2. Metabolism refers to only those reactions that release energy. 3. The half-life of a molecule is the time it takes for 50% of the molecule to be broken down and recycled. 4. Autophagy is an important process that removes worn-out organelles, recycles components, then releases them into the cytosol.
Which of the following is not a biological effect of climate change?
1.Aquatic species threatened by changes in the composition of seawater.
2.Changes in animal migration times and breeding seasons.
3.Changes in the timing of flowering and terrestrial migrations.
4.Decreased production of allergy-inducing pollen by plants.
In males, gonadotropin-releasing hormone stimulates the ____ to secrete ____
a. anterior pituitary; inhibin b. anterior pituitary; FSH and LH c. anterior pituitary; testosterone d. posterior pituitary; FSH and LH e. posterior pituitary; testosterone
Amy just gave birth by cesarean section to a beautiful baby girl. All through her pregnancy, her mammary glands enlarged to prepare for milk production. However, in the day or two following the birth of her baby, Amy cannot eject a drop of the milk that
is so obviously present in her breasts. What hormone is probably missing? A) progesterone B) prolactin C) oxytocin D) estrogen