CSEC Human and Social Biology Paper 2 January 2020 - Free CXC Past Paper with Answers

Muscles A and B are referred to as antagonistic muscles. Define the term 'antagonistic muscles'.

Suzie hates to exercise because she does not like to feel sweaty. As a result, Suzie's muscles have now become very soft and are lacking in tone.

Define the term 'muscle tone'.

State TWO benefits of having well-toned muscles.

State ONE reason, other than improved muscle tone, why exercise is necessary for good health.

Roger likes to have a cup of tea as soon as he arrives at the office. After preparing the tea, Roger lifts the cup to his mouth.

Explain what happens to the muscles in Roger's upper arm as he lifts the cup of tea to his mouth.

Roger's tea is too hot and he quickly releases his hold on the cup. Identify the type of action that takes place and state which part of the central nervous system processes the action.

Figure 4 and Figure 5 show X-ray images of the bones in a normal foot and a damaged foot with a bunion (a painful swelling on the joint of the first toe).

Suggest TWO likely causes for the misalignment of the bones in the foot in Figure 5.

Poor posture could cause compression of the organs in the thorax and abdomen. Suggest THREE other effects that poor posture could have on the body.

Figure 6 shows some organs of the endocrine system.

Identify Organ A and Organ C.

Organ A 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State the effect on the body, if there is an excessive amount of the hormone produced by Organ B.

The pancreas produces two hormones whose actions on the body oppose each other.

Name the TWO hormones whose actions oppose each other.

Both of these hormones, produced by the pancreas, target the liver cells. Describe the action of ONE named hormone on the liver cells and its effects on blood glucose levels.

The table below shows the diets and levels of activity of two groups of individuals, Group A and Group B.

Identify which of the two groups, A or B, is MORE likely to develop diabetes mellitus. State TWO reasons for your answer.

The table below shows the diets and levels of activity of two groups of individuals.

State ONE sign or symptom of diabetes mellitus.

Diabetes is often a complication associated with obesity. Suggest ONE other complication associated with obesity and explain why diet and exercise are important for reducing the risk of developing diabetes mellitus.

Figure 7 shows a diagram of light rays passing through an eye that has a defect.

Figure 7. Light rays passing through an eye with a defect

Identify the eye defect shown in Figure 7. State ONE reason for your answer.

Name the type of lens that could correct the eye defect identified in (a) (i).

Describe how EACH of the following images would appear to an individual with short-sightedness.

Distant objects

Near objects

Errol has been reading for hours. He hears a noise in the distance and looks up to see what is making the noise.

Explain the changes that need to take place in the ciliary muscles, suspensory ligaments and lens during the process of accommodation, in order for Errol to see the distant object clearly.

Erica is 70 years old and has blurry vision in her left eye because of a cataract. Figure 8 shows the movement of light through her left eye.

Figure 8. Movement of light through Erica's left eye

Explain why a cataract causes Erica to have blurry vision.

State ONE way in which Erica's cataract could be corrected.

As Erica got older, it became more difficult for her pupils to dilate. State why this condition would affect her ability to drive at night.

Name TWO diseases that could be transmitted as a result of poorly situated pit latrines.

State TWO factors that must be considered when building a pit latrine. Give ONE reason for EACH factor.

Robert's household has used a pit latrine for years. David is now encouraging his father, Robert, to switch to a septic tank for sewage disposal.

Explain TWO benefits of using a septic tank rather than a pit latrine.

Crude sewage may be discharged into the sea. Care is taken to ensure that it is discharged well out to sea with the outgoing tide to prevent contact with humans. However, it has been recommended that this practice be stopped.

Discuss ONE potential impact of the present practice of sewage disposal on the environment if this recommendation is NOT implemented.

Distinguish between HIV and AIDS.

Distinguish between HIV and AIDS.

Identify the immune cell in the body that is destroyed in an untreated HIV patient and state how the patient is affected as a result.

State TWO symptoms that an AIDS patient is likely to exhibit.

The following is a quotation from Dr Helen Singer Kaplan.

"Counting on condoms is flirting with death."

Comment on the truthfulness of this statement.

Thirteen to fifteen per cent of women whose partners use condoms as the only method of contraception become pregnant within a year. Recommend TWO other reliable contraceptive methods that can be used along with a condom.

Kim is in a monogamous sexual relationship with Branden. She does not use illegal intravenous drugs (drugs injected into the blood stream); however, Branden does. Kim feels confident that her lifestyle choices mean that her risk of contracting HIV is low.

Should Kim feel confident that her risk of contracting HIV is low? State TWO reasons for your answer.