Multi-Select Technology-Enhanced
Bromothymol blue (BTB) is a pH indicator that is also used to detect carbon dioxide (CO). BTB is blue
when pH is basic and Co, is low. BTB is yellow when pH is acidic and Co, is high. BTB is green when
pH is neutral. A group of students are planning to perform an investigation in which they will place
either a stalk of the aquatic plant elodea or a snail in a test tube that contains water with a neutral
pH of 7 and BTB. The students will also include a test tube that contains elodea and a snail. Observing
color change once the tubes have been placed under a growth light for several hours will allow the
students to answer which TWO of the following questions?
A. Do both elodea and snails require oxygen to survive?
B. Does elodea produce oxygen during photosynthesis?
C. Do snails respire faster when placed in a tube with elodea?
D. Do snails use the Co, produced by elodea to produce oxygen?
E. Does photosynthesis performed by elodea remove Co, from the water?
F. Does cellular respiration occur at a higher rate than photosynthesis in the tube with only elodea?

an individual’s sex (i.e., whether they are a male or female) is determined by the sex chromosomes. most people have two sex chromosomes, one that is inherited from their mother and one that is inherited from their father. typically, females have two x chromosomes (xx) and males have one x chromosome and one y chromosome (xy). conditions caused by changes (“mutations”) in genes located on the x chromosome are considered x-linked.

x-linked recessive inheritance

most x-linked conditions are recessive. this means that in a person with two x chromosomes (most females), both copies of a gene (i.e., one on each x chromosome) must have a change or mutation whereas in a person with one x chromosome (most males), only one copy of a gene must have a mutation. a female with a mutation in one copy of a gene on the x chromosome is said to be a “carrier” for an x-linked condition. a male with a mutation in a gene on the x chromosome is typically affected with the condition. because females have two copies of the x chromosome and males have only one x chromosome, x-linked recessive diseases are more common among males than females. however, x-linked recessive diseases can occur in both males and females.

for x-linked recessive disorders, an unaffected carrier mother who has a mutation in a gene on the x chromosome can transmit either the x chromosome with this mutation or a “normal” x chromosome to her children. if the father is unaffected, none of her daughters will be affected and all of her daughters will be unaffected—since they will inherit at least one normal x chromosome from their father. however, each daughter will have a 50% chance of being an unaffected carrier like her mother and a 50% chance of both x chromosomes being normal.

answer:

convection currents in the magma drive plate tectonics. heat generated from the radioactive decay of elements deep in the interior of the earth creates magma (molten rock) in the aesthenosphere. the aesthenosphere (70 ~ 250 km) is part of the mantle, the middle sphere of the earth that extends to 2900 km.