All categories

3 years ago

How did the banned substances DDT and PCBs end up in the ocean?

Biology

1 answer:

lbvjy [14]3 years ago

5 0

Answer:

PCBs and DDT are chemicals that were banned more than 30 years ago, but our air, water, land, and bodies are so contaminated that decades of cleanup efforts have yet to eliminate their threats to our health. Today, food is one of the most likely exposure routes to PCBs.

You might be interested in

Fiona has blue eyes. Which part of each eye is blue?

valkas [14]

The iris is the circular structure in the eye; if the iris is blue, then the eyeball is considered to be blue.

8 0

3 years ago

Read 2 more answers

Chorionic villi are more prolific Select one: a. Adjacent to the yolk sac b. Opposite the cervical os c. Near the implantation s

Ann [662]

Answer:

Adjacent to the yolk sac

Explanation:

Chorionic villi are microscopic and fingerlike projections found near the placenta which contain capillaries, increase surface area of blood that allow blood to flow and transfer nutrients from the mother to the fetus. The chorionic villi is adjacent to the yolk sac because it developed from the yolk sac, villi can extend and contact maternal blood vessels thereby nourishing the embryo and transfering nutrients from the mother to the fetus.

7 0

3 years ago

True-breeding flies with singed bristles (s) and normal wings (L) were crossed to true-breeding flies with normal bristles (S) a

mina [271]

Answer:

The correct answer is -

Possible F2 offspring genotypes and phenotypes:

SsLl: normal bristle, normal wing

Ssll: normal bristle, vestigial wing

ssLl: singed bristle, normal wing

ssll: singed bristle, vestigial wing

Explanation:

In this case, the genes 's' and 'L' and genes 'S' and 'l' are linked, they will be passed on to the gamete together.

The cross would be as follows:

F1:

Parents: singed bristles and normal wings x normal bristles and vestigial wings

Genotype: ssLL SSll

Gametes: sL Sl

F1: SsLl ( normal bristles and normal wings )

For F2,

Parents: normal bristles and normal wings x singed bristles and vestigial wings

Genotypes: SsLl ssll

Gametes: SL, Sl, sL, sl

Cross:

SL Sl sL sl

sl SsLl Ssll ssLl ssll

Thus the possible offspring will have -

SsLl: normal bristle, normal wing

Ssll: normal bristle, vestigial wing

ssLl: singed bristle, normal wing

ssll: singed bristle, vestigial wing

4 0

3 years ago

Motor neurons release the neurotransmitter acetylcholine (ACh) and acetylcholinesterase degrades ACh in the synapse. If a neurop

GuDViN [60]

Answer:B convulsions due to constant muscle stimulation

Explanation:

this is due to Hyperpolarization at the axonal cell membrane from continuous influx of sodium ions .

Normally acetylcholine is an exictatory neurotranmitter, if an inhibitor is applied to block effects of acetylcholinesterase; the action potential will continue to generate , leading to continuous excitation, ( rapid contraction of muscles from increasing action potential, leading to convulsion.

So far nothing to stop the excitatory neurotransmitter. (acetylcholine stimulation at the receptors of neuromuscular junction of post synaptic neuron.

3 0

3 years ago

List the function of nucleus? Name the cell part that has tiny holes?

Andreyy89

To control the activities of a cell, the control center.
by the tiny holes i don't know what you mean but there is ribosomes and lysosomes.
hoped i helped:P

6 0

3 years ago

Read 2 more answers